Improvements in histological tissue specimen processing

ABSTRACT

A method of operating a tissue processor for processing tissue samples. The tissue processor includes at least one retort for receiving tissue samples, at least one container for storing a reagent, and at least one sensor arranged for fluid communication with one or both of the at least one container and the at least one retort for measuring a measured purity level of a reagent. The method includes conducting reagent from the at least one container or the at least one retort to the at least one sensor, automatically measuring a measured purity level of the reagent, checking whether the measured purity level meets a predetermined purity level of the reagent associated with the at least one container, and thereby automatically determining whether the reagent is suitable for processing tissue samples in the tissue processor. Also, a tissue processor for processing tissue samples and a container for storing tissue samples.

This application claims priority from U.S. Provisional PatentApplication No. 62/548,638 filed on 22 Aug. 2017, the contents of whichare to be taken as incorporated herein by this reference.

TECHNICAL FIELD

The present invention relates to a method of operating a tissueprocessor, and to the tissue processor. The tissue processor includes atleast one retort for receiving tissue samples, and at least onecontainer for storing a reagent. It relates more particularly but notexclusively to operating the tissue processor to determine whether areagent is suitable for processing tissue samples in the tissueprocessor. The present invention also relates to a container for storingtissue samples for processing it a tissue processor.

BACKGROUND OF INVENTION

Biological tissue samples, in particular histological tissue samples,are often required in the fields of human and veterinary medicine, inparticular as microscopic prepared specimens for the assessment of cellsand their environment. For microscopic inspection, thin sections of thetissue sample must be prepared for assessment under the microscope, inincident or transmitted light, by an expert.

The production of thin section example using a microtome, requires thatthe tissue sample have a certain strength so that thin, transparentsections having a thickness on the order of micrometres can be producedusing a knife. For this purpose, the tissue sample must first passthrough a treatment process in which it is fixed, dehydrated, cleared,and then infiltrated with a carrier material, preferably meltedparaffin. These processes are often performed successively in a singleunit called a “tissue processor”; this tissue processor includes forthis purpose a closable process chamber called a “retort” that receivesthe various reagents, in particular process media, for carrying out theprocess steps at a suitable temperature and pressure.

These processes for processing the tissue samples in the tissueprocessor are generally provided as a tissue processor workflow. Thetissue processor workflow defines the processes to be applied byselected laboratory stations in the tissue processor, such as theretort. Also, where the tissue sample is to be analysed forhistopathological or histological assessment, the tissue processorworkflow forms part of a histopathology workflow.

Successful processing of tissue samples using a tissue processor relieson immersing the tissue amples in reagents at temperature or ambienttemperature in a sequence of reagent types and increasingconcentrations. Processing of tissue samples with reagent ofinsufficient concentration before progressing to the next reagent typecan result in contamination of the sample and poorly processed tissue.In worst case scenarios, the processed tissue cannot be used fordiagnostic purposes resulting in patients requiring re-biopsy or wherein instances when there is no more sample to excise, such as formelanomas, a failure to diagnose the biopsy.

The reagent quality is dependent on a user to ensure that a sufficientconcentration of reagent is provided in the tissue processor and thatthe concentration is accurately identified, which is susceptible tohuman error. For example, a user may inadvertently assume that a reagentis pure although dilution or contamination of the reagent has occurredduring processing. Furthermore, a user may incorrectly re-fill a reagentcontainer of the tissue processor with the incorrect reagent type,concentration or volume. Additionally, a user may replace an empty orpartially full reagent container in the tissue processor to activate asensor and overcome a system error of insufficient reagent forprocessing.

Therefore, it would be desirable to provide a method of operating atissue processor, and a tissue processor, that can verify reagentquality so as to avoid user error and potential suboptimal tissueprocessing, and which ameliorates and/or overcomes one or more problemsor inconveniences of the prior art.

Successful processing of tissue samples using a tissue processor alsorelies on design of the basket which is loaded into the tissue processorand stores the tissue samples for processing, preferably withincassettes. The basket design is important to ensure that the reagentsused in tissue processing flow to the cassettes and tissue samples toachieve optimal processing. However, baskets currently used in tissueprocessors can interfere with sensors for determining fluid level in theretort in which the basket is placed. This may result in incorrectvolumes or types of processing fluid being used in tissue processingprotocols, which may lead to poorly processed tissue samples.Furthermore, multiple baskets are usually stacked in the retort forefficient processing and/or are transported in a stacked configurationfrom grossing, where formalin soaked samples are prepared, to tissueprocessing stations of the tissue processor. However, the basketscurrently used in tissue processors include a handle, that may interferewith their stacking for these purposes.

Therefore, it would also be desirable to provide a basket for a tissueprocessor that does not interfere with fluid sensors of the tissueprocessor and/or is able to be readily stacked, and which amelioratesand/or overcomes one or more problems or inconveniences of the priorart.

A reference herein to a patent document or any other matter identifiedas prior art, is not to be taken as an admission that the document orother matter was known or that the information it contains was part ofthe common general knowledge as at the priority date of any of theclaims.

SUMMARY OF INVENTION

Viewed from one aspect of the present invention, there is provided amethod of operating a tissue processor for processing tissue samples,the tissue processor including: at least one retort for receiving tissuesamples; at least one container for storing reagent; and at least onesensor arranged for fluid communication with one or both of the at leastone container and the at least one retort for measuring a measuredpurity level of a reagent, the method including the steps of; a)conducting reagent from the at least one container or the at least oneretort to the at least one sensor; b) automatically measuring, by meansof the at least one sensor, a measured purity level of the reagent; c)checking whether the measured purity level meets a predetermined puritylevel of the reagent associated with the at least one container; and d)automatically determining, based on a result of the checking, whetherthe reagent is suitable for processing tissue samples in the tissueprocessor.

In some embodiments, the method further includes the step of providingthe predetermined purity level of the reagent based on reagent data forthe at least one container. The reagent data preferably includes atleast a concentration value of the reagent. The concentration value canbe a percentage dilution of the reagent in water, such as 70%, 80% or100%. The reagent data can also include one or more of a reagent type, areagent name and a container number. The reagent type can include one ormore of a dehydrating fluid, such as ethanol, methanol, isopropanol,butanol, ethylene glycol and various alcohols, a clearing reagent, suchas xylene, di-pentene, D-limonene, 1,1,1, trichloroethane, toluene anddioxane, and an infiltrating material, such as paraffin wax, to name afew.

The method can further include the step of receiving, at the tissueprocessor, the reagent data, for the at least one container from a user.The tissue processor can further include an input device, and thereceiving step can include receiving the reagent data by means of theinput device. The input device can include a control interface of thetissue processor having, for example, a touchscreen display operable bya user. Additionally/alternatively, the tissue processor can include acontroller configured to receive the reagent data from a server orcomputing system, such as through a wireless or hard-wired connection.

The predetermined purity level of the reagent can be one of a thresholdvalue or a tolerance range of values. Preferably, the predeterminedpurity level of the reagent is a concentration level determined based onthe concentration value from the reagent data. The concentration levelcan be a threshold value, where the threshold value can be theconcentration value from the reagent data. Where the concentration levelis a tolerance range of values, the range can be determined based on theconcentration value from the reagent data.

Alternatively, the predetermined purity level n be a density leveldetermined based on the concentration value from the reagent data. Thedensity level can be a threshold value, where the threshold value can bea density value derived from the concentration value from the reagentdata, such as through a calculation based on the pure reagentconcentration or using a lookup table for the reagent. Where the densitylevel is a tolerance range of values, the range can be determined basedon the derived density value.

In some embodiments, the at least one sensor measures at step b) adensity value that represents the measured purity level of the reagent.The at least one sensor is preferably a fluid sensor configured tomeasure the density value of the reagent. The fluid sensor can be adensitometer, and preferably an oscillating pipe density meter.

The method can further include the steps of repeating the measuring stepb) one or more times, and calculating an average of the measured densityvalues, wherein the calculated average represents the measured puritylevel of the reagent. Preferably, the measuring step b) is repeated atleast three times for calculating the average of the three measureddensity values. The red purity level is preferably a concentration valuederived from the measured density value or the average of the measureddensity values, such as through a calculation method based on the purereagent density or using a look-up table for the reagent. Alternatively,the measured purity level can be the measured density value or theaverage of the measured density values.

In some embodiments, the checking step c) of the method includeschecking whether the measured purity level is (i) greater than thethreshold value of the predetermined purity level, or (ii) within thetolerance range of values of the predetermined purity level. Thechecking step is preferably performed on the basis of a comparison ofconcentration values, where the measured purity level is theconcentration value derived from the measured density value or averageof measured density values, and the predetermined purity level is theconcentration value from the reagent data or the tolerance range ofvalues determined based on the concentration value from the reagentdata. However, the checking step can be performed on the basis of acomparison of density values, such as when the predetermined puritylevel is a density level.

In some embodiments, the automatically determining step d) includes:determining that the reagent is suitable for processing tissue sampleswhen the measured purity level is greater than the threshold value orwithin the tolerance range of values; and determining that the reagentis unsuitable for processing tissue samples when the measured puritylevel is less than the threshold value or falls outside the tolerancerange of values. When the reagent is determined to be unsuitable forprocessing tissue samples, the method can further include the step offlagging the at least one container for non-use by the tissue processor.The method can also further include the step of generating, at thetissue processor, a notification signal for a user to check the reagentin the flagged container. The notification signal can be provided to theuser by the input device, such as a control interface having a userdisplay. The notification signal can include a message and/or alarmdisplayed on the user display.

The method can be performed prior to operating the tissue processor toperform a tissue processing protocol using the reagent. Accordingly, insome embodiments the tissue processor includes a dedicated lineconnecting the at least one container or the at least one retort to theat least one sensor, and the conducting step a) of the method includesconducting reagent in the dedicated line from the at least one containeror the at least one retort to the at least one sensor. Preferably, thededicated line is separate from a reagent line that connects the atleast one container to the at least one retort. The conducting step a)can include the transfer or pumping of reagent from the at least onecontainer or the at least one retort along the dedicated line to the atleast one sensor for measuring the measured purity level of the reagent.

In other embodiments, the method is performed when operating the tissueprocessor to perform a tissue processing protocol using the reagent. Thetissue processor can include a reagent line connecting the at least onecontainer and the at least one retort, wherein the at least one sensoris arranged for fluid communication with the reagent line, and whereinthe conducting step a) includes conducting reagent in the reagent linebetween the at least one container and the at least one retort. The atleast one sensor can be one of positioned in the reagent line; orpositioned in a bypass line that receives a portion of the reagent whenthe reagent is conducted in the reagent line.

The method can be perform d on one or both filling of the at least oneretort with reagent; and draining of the at least one retort to removereagent. Accordingly, the method can be performed on starting and/orfinishing of a tissue processing protocol during which the at least oneretort is filled or drained, respectively. In some embodiments, themethod further includes the step of operating the tissue processor tostop filling or draining of the at least one retort to perform at leastmethod steps (b)-(d). The operating the tissue processor to stop fillingor draining can include one or both of: operating the tissue processorto stop filling prior to reagent contacting tissue samples stored in theat least one retort; and operating the tissue processor to stop fillingprior to reagent being delivered to the at least one container.

When the reagent is determined to be suitable for processing tissuesamples, the method can further include the step of operating the tissueprocessor to continue filling or draining of the at least one retort tocomplete the tissue processing protocol. Otherwise, when the reagent isdetermined to be unsuitable for processing tissue samples, the methodcan further include the step of operating the tissue processor toabandon the tissue processing protocol.

In some embodiments, the tissue processor includes a first container forstoring a first reagent and a second container for storing a secondreagent. The method can further include the step of: operating thetissue processor to perform a tissue processing protocol using the firstreagent and the second reagent; and automatically determining a carryover volume of the first reagent from the first container into thesecond reagent from the second container.

In some embodiments, the step of automatically determining the carryover volume includes the steps of: providing an initial volume of thesecond reagent in the second container; and performing the measuringstep b) to measure the following: a density value of the first reagenton draining of the at least one retort; a density value of the secondreagent on filling of the at least one retort; and a density value ofthe second reagent on draining of the at least one retort, wherein thecarry over volume is calculated according to:

$V_{CO} = {\frac{\rho_{C\; 2_{out}} - \rho_{C\; 2_{in}}}{\rho_{C\; 1_{out}} - \rho_{C\; 2_{out}}} \times V}$

wherein: V_(CO)=volume of carry over (L), ρ_(C2) _(out) =measureddensity value of the second reagent on draining of the at least oneretort (kg/m³), ρ_(C2) _(in) =measured density value of the secondreagent on filling of the at least one retort (kg/m³), ρ_(C1) _(out)=measured density value of the first reagent on draining of the at leastone retort (kg/m³), and V=initial volume of the second reagent in thesecond container (L).

Viewed from another aspect of the present invention, there is provided acomputer program product including: a computer readable medium havingcomputer readable program code and computer readable system codaembodied on the medium for, operating a tissue processor, within a dataprocessing system, the computer, program product including: computerreadable code within the computer readable medium for performing themethod of operating a tissue processor as described above.

Viewed from another aspect of the present invention, there is provided atissue processor for processing tissue samples, including at least oneretort for receiving tissue samples; at least one container for storinga reagent; at least one sensor arranged for fluid communication with oneor both of the at least one container and the at least one retort formeasuring a measured purity level of a reagent; and a controllerconfigured to: conduct reagent from the at least one container or the atleast one retort to the at least one sensor; measure, by means of the atleast one sensor, a measured purity level of the reagent; check whetherthe measured purity level meets a predetermined purity level of thereagent associated with the at least one container; and determine, basedon a result of the checking, whether the reagent is suitable forprocessing tissue samples in the tissue processor.

In some embodiments, the controller is further configured to provide thepredetermined purity level of the reagent based on reagent data for theat least one container. The reagent data preferably includes at least aconcentration value of the reagent. The concentration value can be apercentage dilution of the reagent in water, such as 70%, 80% or 100%.The reagent data can also include one or more of a reagent type, areagent name and a container number. The reagent type can include one ormore of a dehydrating fluid, such as ethanol, methanol, isopropanolbutanol, ethylene glycol and various alcohols, a clearing reagent, suchas xylene, di-pentene, D-limonene, 1,1,1, trichloroethane, toluene anddioxane, and an infiltrating material, such as paraffin wax, to name afew.

The controller can be further configured to receive, at the issueprocessor, the reagent data for the at least one container from a user.The tissue processor can further include an input device, and thecontroller can be configured to receive the reagent data by means of theinput device. The input device can include a control interface of thecontroller having, for example, a touchscreen display operable by auser. Alternatively, the controller can be configured to receive thereagent data from a server or computing system, such as through awireless or hard-wired connection.

The predetermined purity level of the reagent can be one of a thresholdvalue or a tolerance range of values. Preferably, the predeterminedpurity level of the reagent is a concentration level determined based onthe concentration value from the reagent data. The concentration levelcan be a threshold value, where the threshold value can be theconcentration value from the reagent data. Where the concentration levelis a tolerance range of values, the range can be determined based on theconcentration value from the reagent data.

Alternatively, the predetermined purity level can be a density leveldetermined based on the concentration value from the reagent data. Thedensity level can be a threshold value, where the threshold value can bea density value derived from the concentration value from the reagentdata, such as through a calculation based on the pure reagentconcentration or using a look-up table for the reagent. Where thedensity level is a tolerance range of values, the range can bedetermined based on the derived density value.

In some embodiments the at least one sensor measures a density valuethat represents the measured purity level of the reagent. The at leastone sensor is preferably a fluid sensor configured to measure thedensity value of the reagent. The fluid sensor can be a densitometer,and preferably an oscillating pipe density meter.

The controller can be configured to measure, by means of the at leastone sensor, the density value that represents the measured purity levelof the reagent two or more times, and can be further configured tocalculate an average of the measured density values, wherein thecalculated average represents the measured purity level of the reagent.Preferably, the density value is measured at least three times forcalculating the average of the three measured density values.Preferably, the measured purity level is a concentration value derivedfrom the measured density value or the average of the measured densityvalues, such as through a calculation method based on the pure reagentdensity or using, a look-up table for the reagent. Alternatively, themeasured purity level can be the measured density value or the averageof the measured density values.

In some embodiments, the controller checks whether the measured puritylevel is (i) greater than the threshold value of the predeterminedpurity level, or (ii) within the tolerance range of values of thepredetermined purity level. The checking is preferably performed on thebasis of a comparison of concentration values, where the measured puritylevel is the concentration value derived from the measured density valueor average of measured density values, and the predetermined puritylevel is the concentration value from the reagent data or the tolerancerange of values determined based on the concentration value from thereagent data. However, the checking step can be performed on the basisof a comparison of density values, such as when the predetermined puritylevel is a density level.

In some embodiments, the controller determines that the reagent issuitable for processing tissue samples when the measured purity level isgreater than the threshold value or within the range of values; andwherein the controller determines that the reagent is unsuitable forprocessing tissue samples when the measured purity level is less thanthe threshold value or falls outside the range of values. When thereagent is determined to be unsuitable for processing tissue samples,the controller can be further configured to flag the at least onecontainer for non-use by the tissue processor. The controller can alsobe further configured to generate, at the tissue processor, anotification signal for a user to check the reagent in the flaggedcontainer. The notification signal can be provided to the user by theinput device, such as a control interface of the controller having auser display. The notification signal can include a message and/or alarmdisplayed on user display.

The controller can determine whether the reagent is suitable forprocessing tissue samples prior to operating the tissue processor toperform a tissue processing protocol using the reagent. Accordingly, insome embodiments the tissue processor includes a dedicated lineconnecting the at least one container or the at least one retort to theat least one sensor, and the controller conducts reagent in thededicated line from the at least one container or the at least oneretort to the at least one sensor. Preferably, the dedicated line isseparate from a reagent line that connects the at least one container tothe at least one retort. Conducting reagent can include the transfer orpumping of reagent from the at least one container or the at least oneretort along the dedicated line to the at least one sensor for measuringthe measured purity level of the reagent.

In other embodiments, the controller determines whether the reagent issuitable for processing tissue samples when operating the tissueprocessor to perform a tissue processing protocol using the reagent. Thetissue processor can include a reagent line connecting the at least onecontainer and the at least one retort, wherein the at least one sensoris arranged for fluid communication with the reagent line, and whereinthe controller conducts reagent in the reagent line between the at leastone container and the at least one retort. The at least sensor can beone of: positioned in the reagent line; or positioned in a bypass linethat receives a portion of the reagent when the reagent is conducted inthe reagent line.

The controller can determine whether the reagent is suitable forprocessing tissue samples during one or both of: filling of the at leastone retort with reagent; and draining of the at least one retort toremove reagent. Accordingly, the controller can determine thesuitability of the reagent on starting and/or finishing of a tissueprocessing protocol during which the at least one retort is filled, ordrained, respectively. In some embodiments, the controller is furtherconfigured to operate the tissue processor to stop filling or drainingof the at least one retort to determine whether the reagent is suitablefor processing tissue samples. The controller can operate the tissueprocessor to stop filling or draining by one or both of: operating thetissue processor to stop filling prior to reagent contacting tissuesamples stored in the at least one retort and operating the tissueprocessor to stop filling prior to reagent being delivered to the atleast one container.

When the controller determines that the reagent is suitable forprocessing tissue samples, the controller can be further configured tooperate the tissue processor to continue filling or draining of the atleast one retort to complete the tissue processing protocol. Otherwise,when the controller determines that the reagent is unsuitable forprocessing tissue samples, the controller can be further configured tooperate the tissue processor to abandon the tissue processing protocol.

In some embodiments, the tissue processor includes a first container forstoring a first reagent and a second container for storing a secondreagent. The controller can be further configured to: operate the tissueprocessor to perform a tissue processing protocol using the firstreagent and the second reagent; and determine a carry over volume of thefirst reagent from the first container into the second reagent from thesecond container.

In some embodiments, the controller is configured to determine the carryover volume by: receiving an initial volume of the second reagent in thesecond container; and measuring, by means of the at least one sensor,the following: a density value of the first reagent on draining of theat least one retort; a density value of the second reagent on filling ofthe at least one retort; and a density value of the second reagent ondraining of the at least one retort, wherein the controller calculatesthe carry over volume according to:

$V_{CO} = {\frac{\rho_{C\; 2_{out}} - \rho_{C\; 2_{in}}}{\rho_{C\; 1_{out}} - \rho_{C\; 2_{out}}} \times V}$

wherein: V_(CO)=volume of carry over (L), ρ_(C2) _(out) =measureddensity value of the second reagent on draining of the at least oneretort (kg/m³), ρ_(C2) _(in) =measured density value of the secondreagent on filling of the at least one retort (kg/m³), ρ_(C1) _(out)=measured density value of the first reagent on draining of the at leastone retort (kg/³), and V=initial volume of the second reagent in thesecond container (L).

Viewed from another aspect of the present invention, there is provided acontainer for storing tissue samples for processing in a tissueprocessor, wherein the container is configured to be accommodated in aretort of the tissue processor and provide access to the stored tissuesamples for processing with a process fluid in the retort, wherein theretort includes at least one sensor for detecting a level of the processfluid in the retort, and wherein the container is configured to minimiseinterference with the at least one sensor.

In some embodiments, the contain is a basket for storing the tissuesamples. In some embodiments, the at least one sensor is an opticalsensor, and the container includes at least one non-reflective surfacefor minimising interference with the optical sensor. Preferably, the atleast one non-reflective surface includes an opaque material. The opaquematerial ideally minimises reflections that can occur during use of theoptical sensor to detect the level of the process fluid.

The container can be configured to releasably receive one or more clipshaving the at least one non-reflective surface. For example, thecontainer can be a basket and the one or more clips can be releasablyattached to openings in side portions of the basket.Additionally/alternatively, the container can include side portionshaving the at least one non-reflective surface.

Viewed from another aspect of the present invention, there is provided acontainer for storing tissue samples for processing in a tissueprocessor, wherein the container is configured to be accommodated in aretort of the tissue processor and provide access to the stored tissuesamples for processing with a process fluid in the retort, wherein thecontainer includes a retractable handle to facilitate stacking of aplurality of the containers.

In some embodiments, the container is a basket for storing the tissuesamples. In some embodiments, the container further includes areceptacle having a central recess for receiving the handle in aretracted position. The handle is preferably integral with thereceptacle. Integrating the handle into the receptacle can avoid anydependency on secure attachment of a lid, thereby reducing the risk ofdropping the container during transport.

The container can further include a lid having a slot through which thehandle is extendable to an extended position. Ideally, the handle doesnot protrude or only partly protrudes through the slot of the lid in theretracted position. In some embodiments, the receptacle includes a baseportion having a slot for receiving at least part of a handle of acorresponding container. The slot in the base portion can receive apartly protruded handle of a corresponding container for ease ofstacking.

Viewed from yet another aspect of the present invention, there isprovided the tissue processor as described above and further includingthe container for storing tissue samples as described above.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be described in greater detail with reference tothe accompanying drawings in which like features are represented by likenumerals. It is to be understood that the embodiments shown are examplesonly and are not to be taken as limiting the scope of the invention asdefined in the claims appended hereto.

FIG. 1 is a simplified schematic block diagram of a prior art tissueprocessor showing the basic elements thereof;

FIG. 2 is a detailed schematic block diagram of the prior art tissueprocessor of FIG. 1 showing air and reagent lines;

FIG. 3 illustrates a perspective view of the prior tissue processor ofFIGS. 1 and 2;

FIG. 4 illustrates a perspective cute-away view of a retort of the priorart tissue processor shown in FIG. 3;

FIG. 5 illustrates a similar perspective cut-away view of the retort ofFIG. 4 with cassette baskets in place;

FIG. 6 illustrates a front view of the retort shown in FIG. 4;

FIGS. 7a and 7b illustrate views of a reagent valve used in the priorart tissue processor of FIGS. 1 to 3;

FIG. 8 illustrates a rear view of the tissue processor shown in FIG. 3;

FIGS. 9a and 9b are simplified schematic block diagrams of a tissueprocessor according to embodiments of the invention, showing a reagentline connecting a container and a retort with a sensor arranged in thereagent line.

FIGS. 9c and 9d are simplified schematic block diagrams of a tissueprocessor according to embodiments of the invention, showing a reagentline connecting a container and a retort with a sensor arranged in abypass line in FIG. 9c and in a dedicated line in FIG. 9 d;

FIG. 10 is a simplified schematic block diagram of a tissue processoraccording to an embodiment of the invention, showing a plurality ofcontainers connected by a reagent valve to two retorts with a sensorarranged in each reagent line;

FIG. 11 is a flow chart of method of operating a tissue processor, thatcan be performed by a controller of a tissue processor, according to anembodiment of the invention;

FIG. 12 is a simplified flow chart of a workflow for reagent screeningon retort filling incorporating the method of FIG. 11:

FIGS. 13a to 13c are more detailed flow charts of workflow for reagentscreening shown FIG. 12;

FIGS. 14a and 14b are perspective views of a container for storingtissue samples with a retracted handle, showing top and bottom views,respectively, according to embodiments of the invention; and

FIGS. 15a and 15b are perspective views of the container for storingtissue samples of FIGS. 14a and 14b showing an extended handle, with andwithout a lid, respectively, according to embodiments of the invention.

DETAILED DESCRIPTION

Embodiments of the invention are discussed herein by reference to thedrawings which are not to scale and are intended merely to assist withexplanation of the invention. The inventive method, tissue processor andcomputer program product have utility in the operation of a tissueprocessor for processing tissue samples for histological analysis. Theinventive method, tissue processor and computer program product haveparticular utility in the operation of a tissue processor to determinewhether a reagent is suitable for processing tissue samples in thetissue processor, either prior to or during operation of the tissueprocessor to perform a tissue processing protocol using the reagent.Furthermore, the inventive container for storing tissue samples hasutility in minimising interfere with fluid sensors of a tissue processorand/or is able to be readily stacked for ease of use.

A prior art tissue processor 10 is described in International PCTApplication No. PCT/AU02/01337, publication No. WO 03/029845, titled“Histological Tissue Specimen Treatment”, published 10 Apr. 2003 andfiled by Vision Biosystems Limited. The tissue processor 100 ofpreferred embodiments of the invention includes similar components tothe prior art tissue processor 10 disclosed in WO 03/029845 and,therefore, it will be convenient to hereinafter describe the prior arttissue processor 10 disclosed in that application. It should beappreciated, however, that embodiments of the invention are not limitedto having identical components or all of the components of the prior arttissue processor 10 disclosed in WO 03/029845 and as described herein.For example, embodiments of the invention may be directed to tissueprocessors or methods of operating tissue processors that differ fromthe prior art tissue processor 10 and that only comprise a singleretort, as will be described herein.

Description of Histological Tissue Processor

In FIG. 1 an example of a general schematic of a prior art tissueprocessor 10 is shown, indicating major features such as retorts 12 and14, four infiltrating baths 16-22, containers 26, reagent valve 40,manifold 38, and air pump 44. There are three main fluid sub-systemsconnecting the major elements, one sub-system being the air lines 30from pump 44 to infiltrating baths 16-22 and retorts 12 and 14. A secondsub-system being infiltrating lines 32 connects infiltrating baths 16-22to the retorts 12 and 14. A third sub-system is reagent lines 34connecting the containers 26 to the reagent valve 40 and the retorts 12and 14. Valving as shown in FIG. 2 ensures that fluid flows along thelines to the correct destination, and FIG. 2 shows a specific embodimentof fluid line connection and valve placement relative to theaforementioned elements. The electrical connections between thecontroller 25, valves, pump 44 and other elements have been omitted fromFIG. 2 for clarity, and are considered standard fittings. Also omittedfrom FIG. 2 are the numerous containers 26 (see for example, containers27 and 29 of FIG. 2) and their respective connections to the reagentvalve 40, to provide clarity. The omitted connections are identical tothe connections shown in FIG. 2.

The schematic of FIG. 2 is embodied in the example shown in FIGS. 3 and8. With reference to FIGS. 3 and 8, the prior art tissue processor 10includes control interface 24 that employs a graphical user interface toenable a user to operate the prior art tissue processor 10 by controller25. In the present embodiment, the controller 25 is located in cabinet11, however the interface 24 and controller 25 may be locatedseparately, for example s part of a stand-alone personal computer. Thecontroller 25 may include a personal computer processor such as aCeleron chip by Intel Corporation located on an ETX form factor PCB (notshown). The controller 25 may contain or store a number of predefinedprotocols (or steps) for processing tissue, the protocols being storedin a non-volatile memory such as hard drive. Protocols may beprogrammable by the user to implement a number of steps for tissueprocessing, or they may be predefined. Typical protocol parametersinclude which reagents are to be applied to the samples, how long thereagents are to be applied, the temperature at which the reagents areapplied, whether agitation is to take place, and whether ambientpressure in the retort is to be changed.

In FIG. 3, the retorts 12 and 14 can be seen in front of infiltratingbaths 16-22. The lids for the retorts 12 and 14 have been removed forclarity, as have the lids for the infiltrating baths 16-22. An open lid15 of retort 14 is shown, for example, in FIG. 8. In the presentembodiment, each retort 12 and 14 would have a lid (not shown), and eachpair of infiltrating baths would also have a lid 17 and 19 (shown inFIG. 8). The lids may seal with the retorts 12 and 14 and baths 16-22when in a closed position. The containers 26 may be located under theretorts 12 and 14 so as to be accessible to a user. The controllerinterface 24 in FIGS. 3 and 8 employs a touch screen, however otherinput and display devices may be employed. Also located under theretorts 12 and 14 is a filter unit 52, which typically includes a carbonfilter to absorb vapours from air expelled from the processor 10.

In FIG. 8, the various fluid lines such as reagent lines 34 from reagentcontainers 26 can be seen attached to a reagent valve 40. The reagentvalve 40 may have inputs from all containers 26, and a single output toretorts 12 and 14. A number of air lines can also be seen connectingmanifold 38 to the reagent bottles 26. The connections between variouselements in FIG. 8 are shown schematically in FIG. 2.

One embodiment of retort 12 is shown in FIGS. 4-6, including areceptacle 13 for receiving baskets 62 containing tissue samples. Thereceptacle 13 has a working capacity of 5.5 litres, however it may notnecessarily be completely filled during each step of a protocol. Whenlocated in the processor 10, the retort 12 may be rotated 10 degreesforward towards the front the processor 10. This allows easier access tothe baskets 62, as well providing drainage point, which is lowermost inthe receptacle 13, minimising residuals remaining in the retort 12 afterdraining.

Sensors 52 are used to detect the level of fluid within the retort 12,so that the controller 25 can ascertain when to turn the pump 44 on oroff, or open and close the appropriate valves, as described below. InFIG. 6, the placement of the three sensors 52 can be seen. The lowermostsensor 52 detects when the level of liquid, for example reagent orinfiltrating fluid, is above a minimum level. The minimum level mayrepresent a partially filled receptacle 13, which is desirable whenoperating in economy mode. This is desirable when two or less baskets 62are to be processed at once, whereupon only approximately 3.8 litres offluid are required to cover the baskets 62 and samples containedtherein. As the baskets may be various sizes, the level of the lowermostsensor 52 and therefore fill volume for economy mode can vary indifferent embodiments of the retort 12. The middle sensor 52 detectswhen the level of liquid typically covers three baskets 62, which is anormal full load. The top sensor 52 detects an overfill situation. Inthis particular embodiment, the sensors 52 are optically based relyingon a change in refractive index when liquid comes into contact with aprism (not shown) of the sensor 52. Each basket 62 may holdapproximately 100 samples either in individual cassettes or placeddirectly into the basket 62. Thus a full load for the embodiment of theretort 12 shown in FIGS. 4-6 is approximately 300 samples. The retorts12 and 14 may be made larger or smaller depending on requirements.

Also shown in FIG. 6 is a temperature sensor 53, which is mounteddirectly to the retort 12, and the temperature sensor 54, which ismounted to a heating mat 55. The retort 12 is heated to ensure correctreagent, or infiltrating fluid temperature. Placing a temperature sensor53 directly on the retort 12 allows the fluid temperature within to bemeasured more accurately than by measuring the temperature of theheating mat 55, especially where the fluid used may have low thermalconductivity. The temperature sensor 54 of the heating mat 55 may thenbe kept at a maximum while the temperature of the retort 12 is below themaximum processing temperature or more precisely, the desired operatingtemperature of the retort 12, providing more rapid heating than if onlyone temperature sensor 54 was employed.

Port 56 shown in FIG. 6 allows connection of an air line 30 to theretort 12. Retort manifold 57 also allows connection of infiltratingline 32 and reagent 34 through a common entry point (not shown) at thebottom of the receptacle 13. In FIG. 2, retort manifold 57 incorporatesvalves ret1-vrgt and ret1-vwax, and is located at the front of the priorart tissue processor 10 so that the lean angle of 10 degrees of theretort 12 causes all fluid to drain towards the common entry point.

In FIGS. 4 and 5, the interior of the receptacle 13 is shown, includingagitator 70. Agitator 70 is magnetically coupled to an electric motor58, and may be driven at a number of speeds dictated by controller 25.The baskets 62 each contain up to 100 tissue samples. The baskets 62 aresupported clear of the agitator on posts 59 as shown in FIG. 4.

In the present example, retorts 12 and 14 are of identical construction,size and operation, however one retort may be larger or more volumousthan the other. Connections to and from retort 12 are duplicated onretort 14.

In FIG. 2, pressure relief valves 48 are shown in fluid communicationwith air lines 30, retorts 12 and 14, and the infiltrating baths. Anyoverpressure in these lines will result in excess air being vented towaste through the manifold 38 and filter 47. The pressure may bemeasured by pressure sensors 46 as shown in FIG. 2.

A list of valve functions is as follows with reference to FIG. 2:

Valves ret1-vwst and ret2-vwst connect retorts 12 and 14 to wastecontainer 72, when a waste cycle is required. Only one retort will beemptied at once and therefore these valves only open one at a time. Inanother embodiment, the valves ret1-vwst and ret2-vwst may be omitted,and waste container 72 may be directly connected to the reagent valve40. To drain reagent to waste, the reagent valve 40 connects to thereagent line 34 connected to the waste container 72, and the valve onthe retort 12, 14 is opened to drain reagent directly to the wastecontainer 72.

Valves ret1-vrgt and ret2-vrgt allow reagent flow into and out of theirrespective retorts during filling and draining of the retort. Whendraining a retort, these valves are open so that reagent may flow backdown the reagent line 34 and back into the same reagent container 26from whence it came. It can be seen that air valves ret1-vfls andret2-vfls connect to the reagent line 34 between the ret1-vrgt andret2-vrgt valves. These air valves are used to purge excess reagent fromthe reagent lines after filling one retort. This is desirable as usingreduced pressure to draw fluid into a retort 12, 14 reduces fluidpressure along the whole reagent line 34, and therefore when pressure isrestored to the reagent line 34 some reagent may travel up the line ofthe retort 12, 14 that was not filled. Opening these valves, or openingthe valves and pumping air down the air lines into the reagent linesclears excess reagent, preventing or reducing cross contamination.

Valves ret1-vwax and ret2-vwax connect the retorts 12, 14 to theinfiltrating baths 16-22, via infiltrating lines 32 and valves wb1-vwxand wb4-vwx. Valves ret1-vwax opens when infiltrating fluid is to enteror drain from retort 12, and wb1-vwx to wb4-vwx open one at a timedepending on where the infiltrating fluid is being sourced. Theinfiltrating line 32 between the infiltrating baths 16-22 and retorts12, 14 is heated to ensure that the infiltrating material does notharden in the lines.

Valves ret1-vair and ret2-vair are used to control air from the air pumpto the retorts. Air may be supplied either at a positive pressure toambient, or withdrawn from the retorts 12, 14 so that pressure insideone or both retorts 12, 14 is below ambient pressure. These valvesdetermine which retort 12, 14 is in fluid connection with the air pump44. Also air-vprs must be open to allow communication between the pump44 and the valves, otherwise air is directed toward wax-air valve,connected to the infiltrating baths 16-22.

The reagent valve 40 is shown in FIGS. 7a and 7 b, and includesconnections between the reagent lines 34 from the reagent containers 26on the input side, and outlet 35, which is fluidly connected to theretorts 12 and 14. The reagent valve 40 selects which reagent container26 will be in fluid communication with the reagent line 34 connected tothe retorts 12, 14. In the present embodiment, the reagent lines 34 fromthe reagent containers 26 are arranged in a circle attached to thereagent valve housing 37. In the present embodiment, the reagent valve40 is in the form of a rotary valve, having two ceramic discs 39 and 41,disc 39 having a single aperture 43 a aligned with aperture 43 b to forma conduit for reagent. The discs 39, 41 are mounted coaxially andadjacent each other and rotate together according to the positiondictated by the controller 25. Disc 45 has an aperture for each reagentline 34, although in FIG. 7b only one aperture is in the plane of thecross section. The rotating discs 39 and 41 rotate with respect to disc45, driven by stepper motor 49 such that the apertures align to providea flow path from the outlet 35 (and therefore one retort) to a reagentcontainer 26. In order to assist with sealing between the discs 39, 41and 45, a plate 51 applies pressure to the discs. In this way, anyreagent line 34 and therefore any reagent container 26 can be selectedby the controller 25 to be in fluid communication with one of theretorts 12 or 14. This type of valve has small internal volume andtherefore minimises cross contamination. Further, the reagents aredrained back into the reagent containers 26 after each step andtherefore little reagent remains to contaminate the subsequent reagent.It should be noted that the infiltrating fluid does not pass through thereagent valve 40. This separation of fluid flow prevents the reagentvalve 40 from clogging and reduces the amount of cleaning of the valve40.

In use, the tissue samples to be processed are typically placed intocassettes (not shown) for placement basket 62. Generally, tissue samplesexpected to have similar processing times and to be exposed to the sameprocessing protocol are placed together in the same basket 62. Thebasket 62 containing the tissue samples is then placed into one of theretorts 12 or 14, and the lid closed, forming a sealed enclosure. Anoperator may then enter data into the control interface 24 to instructthe controller 25 of the protocol to be followed. The protocol may beprogrammed step by step, for example indicating the time, temperature,pressure, agitation and reagent for each step, or a pre-programmedprotocol encompassing all steps may be selected.

The first step in a protocol, once the lid 17 of the retort 12 issecured, may be to fill the chosen retort (in this example retort 12 ischosen) with a fixing solution. A typical fixing solution is formalin,which may be held in one or more reagent containers 26. In order to fillthe retort 12 with fixing solution, the pump 44 is switched on andvalves open the air lines from the retort 12 to the inlet side of thepump, pumping air from the retort 12 chamber. The reagent valve 40 isset to a position that fluidly connects the reagent line 34 of theretort 12 to the specified reagent container 26 for formalin. Othervalves are opened along the reagent lines 34 from the retort 12 to thereagent valve 40. The reduced pressure in the retort 12 is sufficient todraw fluid out of the reagent container 26, through the reagent valve 40into the reagent lines 34 and into the retort 12. The retort is heatedby heater pads to a predetermined temperature selected and controlled bythe controller 25. Sensors 53 and 54 may be used to control thetemperature of the retort 12, and therefore the tissue and any reagentcontained therein. One or more sensors 52 in the retort as shown inFIGS. 4 and 6, may be used to detect the reagent level. When the reagentlevel in the retort 12 is sufficient, typically to cover the baskets 62as seen in FIG. 5, the pump may be turned off or otherwise disengagedfrom the retort 12, for example by closing valve ret1-vrgt shown in FIG.2.

After a length of time determined by the controller 25 (typically asprogrammed by the user), the reagent may be removed from the retort 12.This is accomplished by opening valve ret1-vair in the air line 30 andopening valve ret1-vrgt in the reagent line 34. Reagent will then drainfrom the retort 12 back into the reagent container 26 from which itcame, or back into a different reagent container 26, or to waste,according to the position of the reagent valve 40 determined by theprogrammed protocol. To assist in draining, the retort 12 may bepositively pressurised by air from the pump 44, supplied along the airlines 30. In the present embodiment the reagent drains back to itsoriginating container 26. If the reagent is contaminated, or has beenused for the predetermined number of samples or washes, then it isdrained to waste using a separate waste cycle.

During the retort filling with reagent from a reagent container 26, theair pumped from the retort 12 flows down an air line 30, some of whichflows back through manifold 38 and into the reagent container 26,recirculating some of the air from the retort 12. Excess air pumped fromthe retort 12 will flow out through a condensing mechanism such as acondensing coil 51, and/or a carbon filter 47, both of which aredesigned to remove volatile organic or other compounds from the airbefore it reaches the atmosphere. The processor 10 may have an outletconnection that allows the filtered air to be vented or further filteredby apparatus external to the processor 10.

The second step in tissue processing may be the dehydration step. Themethodology employed to draw dehydrating reagent into the retort 12 maybe the same as described above, as the dehydrating reagent will bestored in a reagent container 26. The dehydrated fluid may contain afluid such as an alcohol, for example ethanol. The dehydrating fluid mayalso contain some water, either intentionally added, or, where thedehydrating fluid has been re-used, water removed from the previoussamples. There may be a number of steps of the protocol wheredehydrating fluid is applied to the sample in the retort 12, 14, and ateach step a different dehydrating fluid may be used. For example, afluid may be used that has less water than a previous fluid, to draw outmore moisture from the sample at each wash. The dehydrating fluid mayadditionally or alternatively contain isopropanol. Later washes withisopropanol provide properties that may be advantageous, as will bedescribed below. Further additives commonly used in the tissue processordehydration fluids may be used, as the prior art tissue processor 10 isintended to be compatible with known dehydration fluids.

On a final wash with dehydrating fluid, the fluid is drained completelyfrom the retort 12, 14. This is accomplished by opening valves from theair pump 44 as well as pumping air into the reagent lines 34 to clearthe reagent. A vapour flush may be employed where the pump 44 flushesfresh air into the retort 12, 14 to clear any vapour from the reagent,such as a dehydrating fluid. Significant vapour may be present as thedehydrating fluid may have high partial pressure at the retort operatingtemperature. After the dehydrating step, a drying step may be employed,where the retort 12, 14 is heated by the heating mats 55, while air ispumped through the chamber by the air lines 30. This removes excessdehydrating fluid. The drying step may take several minutes or more, andthe retort 12, 14 may be heated to 85 degrees Celsius, depending on thedehydrating fluid chosen and the sensitivity of the tissue samples toheat.

Another step in tissue processing is infiltrating of the samples. Thisis typically accomplished by an infiltrating material such as a paraffinwax. The wax is held in the infiltrating baths 16-22, which are heatedto the desired temperature above the waxes melting temperature, which istypically 54 degrees Celsius. Wax pellets are typically added to aninfiltrating bath 16-22, which heats the pellets until they melt andachieve a suitable temperature. Alternatively, pre-molten wax may beadded directly to the baths 16-22. The wax is held at the elevatedtemperature, typically 65 degrees Celsius, until required. The prior arttissue processor 10 shows four infiltrating baths 16-22, however theremay be more or less depending on retort and infiltrating bath volume.The infiltrating lines 32 run from the infiltrating baths 16-22 to bothretorts 12 and 14, and include valves such as ret1-max and ret2-max,that allow one, some, or all baths 16-22 to be fluidly connected to oneof the retorts 12, 14. The arrangement of the baths 16-22, valves, andinfiltrating material lines enables samples in one retort 12, 14 to bewashed with up to four different infiltrating materials. Further, theinfiltrating material may be heated in one or more baths 16-22 while theprocessor 10 is in operation and drawing infiltrating material from theremainder of the baths 16-22.

During the infiltrating step, the wax is drawn into the retort 12 byopening the valve between the retort 12 and appropriate infiltratingbath 16-22, such as ret1-vfls, then reducing the pressure in the retort12 using the pump 44 and opening valves air-vprs and ret1-vair. Thereduced pressure in the retort 12 draws the wax into the retort 12.Typically, the pressure may be −20 to −80 kpa gauge, however a widevariety of pressures may be used, and these are user programmable viathe controller 25. The wax may be heated to a temperature above orapproximately the same as the boiling temperature of the dehydratingfluid used in the last or last few washes. If an isopropanol is used,the boiling temperature will be approximately 82 degrees Celsius atatmospheric pressure. Ethanol typically boils at 78 degrees Celsius.After the retort 12 has been draining of dehydrating fluid, some fluidremains on or absorbed by the tissue samples. The tissue samples maythen be subjected to a drying stage as described above to remove furtherdehydrating fluid, and the retort 12 flushed with clean air. Wax is thendrawn into the retort 12. Upon contact with the heated wax, theremaining dehydrating fluid is evaporated or boiled off the tissuesamples, and the wax replaces the dehydrating fluid, thus infiltratingthe samples. The pump 44 may continue to draw off air or vapour from theretort 12 to reduce the pressure in the retort 12, which will reduce theevaporation temperature of the dehydration fluid. As an example, thepressure in the retort 12 may be reduced by 50 kpa gauge, resulting in aboiling temperature of approximately 52 degrees Celsius for theisopropanol. Reducing temperatures of the wax contacting the tissuesamples may provide an advantage, for example where certain types oftissues do not perform well when exposed to high temperatures. Typicallythe paraffin wax used (Paraplast+ from Oxford Laboratories) melt atabout 54 degrees Celsius. Other infiltrating materials may be usedincluding resins used in histological processes for infiltrating tissuesamples. In the present example, the alcohol used at the last stage,isopropanol, is not substantially miscible with paraffin wax. This meansthat infiltrating fluid is unlikely to penetrate the tissue sample ifthe previous fluid in the retort was miscible with the infiltratingfluid. Boiling the volatile dehydrating material off therefore enablesthe omission of step whereby an intermediary fluid such as xylene, whichis miscible in alcohol and paraffin wax, is required. Xylene hasundesirable properties in a laboratory. However, xylene will alsoevaporate when exposed to temperature around 80 degrees, especially whenapplying a vacuum as described herein has lowered the pressure insidethe retort 12. Thus the present example enables the tissue samples to beused without a xylene wash cycle, but also may be used with fluids suchas xylene. There are advantages in not using xylene, including thatxylene is miscible in wax, and therefore can be absorbed into the wax asa contaminant. However, in some instances it is desirable to use xylene,for example when the tissue requires clearing and the dehydrating fluidsuch as isopropanol is deemed to be insufficient. Further, xylene may beused after a processing cycle to clean excess wax from the retort 12,and therefore xylene may be present in the prior art tissue processor10.

It is possible to clean the infiltrating fluid of some of the volatilecontaminants, such as dehydrating fluid, clearing fluids such as xylene,by holding the wax in the bath 16-22 and reducing the pressure in thebath 16-22. This clean cycle is done with the bath lid closed, whereuponthe reduced pressure and holding the infiltrating material at anelevated temperature such as between 60 degrees and 100 degrees Celsius.The temperature may be held between 65 degrees and 85 degrees Celsius.By volatile material, it is meant that at the temperatures mentionedherein, and/or at reduced pressure, the material will boil or evaporate.

The vapour pressure of the dehydration fluid within the air line 30 inthe container 26 may also be reduced, for example, by venting air in theretort 12, either while maintaining a low pressure or cycling throughpressure ranges. The infiltrating fluid may be held in the bath 16-22 atan elevated temperature for several hours to clean away contaminants.

The use of two retorts 14 allow two sets of baskets 62 to be processedeither simultaneously or with an overlap. Thus one retort 12 can beloaded and a protocol begun while the other retort 14 is mid-way throughthe same or a different protocol. This provides additional flexibilityin the prior art tissue processor 10.

The tissue samples referred to may be human or animal tissue samples, orsamples from plant material.

An example protocol for tissue samples; such as a 3 mm punch humanbiopsy sample, will now be described.

Time Temp Retort Step Reagent (min) (c.) Pressure Agitation 1 Formalin 560 Ambient Yes 2 50/50 Ethanol water 25 60 Ambient Yes 3 80/20 Ethanolwater 35 60 Ambient Yes 4 Isopropanol 30 60 Ambient Yes 5 Paraffin Wax40 60 Vacuum Yes 6 Paraffin Wax 5 60 Vacuum Yes Total processing time140Another protocol is as follows:

Time Temp Retort Step Reagent (min) (c.) Pressure Agitation 1 Formalin60 40 Ambient Yes 2 80% Ethanol 45 40 Ambient Yes 3 90% Ethanol 45 40Ambient Yes 4 100% Ethanol 60 40 Ambient Yes 5 100% Ethanol 60 40Ambient Yes 6 100% Ethanol 60 40 Ambient Yes 7 100% Ethanol 60 40Ambient Yes 8 Isopar or d-limonene 60 40 Ambient Yes 9 Isopar ord-limonene 75 40 Ambient Yes 10 Isopar or d-limonene 75 40 Ambient Yes11 Paraplast 70 60 Vacuum Yes 12 Paraplast 60 60 Vacuum Yes 13 Paraplast60 60 Vacuum Yes Total processing time 790

From the above it can be seen that xylene is not required in thisprotocol, and that the protocol has few steps, saving time.

A contamination detector 68 may be placed in the reagent line 34 todetect the presence of contaminants in the reagents. To drain the retort12, the pump may increase pressure in the retort 12 by pumping air alongthe same air lines 34 as used to draw reagent into the retort 12. Wastereagent may be drained into a reagent container 26, or be expelled towaste port 72. Infiltrating fluid may also be drained from the retort 12to waste 70 by this method, and similarly infiltrating fluid may bedrained from the baths 16-22 using positive pressure.

In the above examples the dehydrating fluid is immiscible with theinfiltrating material. However, the above process offers advantages evenif a clearing cycle is used, where the clearing fluid is miscible withthe dehydrating fluid and the infiltrating material. Further, additivesmay be used to increase the clearing properties of the dehydratingmaterial, as well as increasing the miscibility of the fluids in thedehydrating and infiltrating steps.

While raising the temperature of the infiltrating fluid above theboiling temperature of the dehydrating reagent (or clearing reagent)will result in faster removal of the reagent, reagent will still beremoved at or around the boiling temperature provided the partialpressure in the retort 12 is lower than the partial pressure of thereagent at the given temperature. This can be accomplished by reducingthe pressure in the retort 12, then allowing some fresh air into theretort. Bringing fresh air into the retort 12 while removing air ladenwith vapour will reduce the partial pressure of reagent in the air inthe retort 12 thus promoting more evaporation of the reagent. If thereagent is miscible with the infiltrating fluid it may not be necessaryto remove all the reagent to obtain infiltration. However, if thesamples can withstand the temperature it is preferable to raise thetemperature of the infiltrating fluid within the retort 12 to atemperature above the boiling temperature of the reagent for the givenpressure. A temperature about the boiling temperature of a reagent for agiven pressure may be typically a few degrees, such as 5 degreesCelsius, of the boiling temperature.

Other dehydrating fluids are contemplated as being able to be used withthe prior art tissue processor 10, such as methanol, butanol, ethyleneglycol, propylene glycol, industrial methylated spirits, denaturedalcohol (including alcohol denatured with kerosene, benzene or brucine),reagent grade alcohols, acetone and combinations thereof, however thislist is merely representative and is not intended to encompass anexhaustive list of reagents useful in the prior art tissue processor 10described herein.

Clearing reagents such as di-pentene, D-limonene, 1,1,1,trichloroethane, toluene, and dioxane are also contemplated, and againthis list is meant to be indicative of the types of reagents that may beused, rather than an exhaustive list. The reagents above, and otherreagents suitable for histological processes such as dehydrating,clearing or a combination thereof, may be used in the present apparatuswith the step of evaporating the reagent from the sample using heatingof the infiltrating fluid, provided the reagents evaporate withoutleaving a residue. While reagents such as butanol have a boiling pointof approximately 118 degrees Celsius at atmospheric pressure, theboiling point drops dramatically with a reduction in ambient pressure.While it is believed preferable to not heat most tissues above 85degrees Celsius, some types of well fixed tissue will survive thistemperature without damage, and therefore higher temperatures may beused, increasing the range of reagents useful in the abovementionedprocesses. Accordingly, the upper temperature which may be used isdependent on the tissue, and therefore in well fixed tissue,temperatures may exceed 100 degrees Celsius. Reducing pressure theretort 12 will assist in reducing temperatures in the retort 12 byreducing the boiling point of reagents.

Infiltrating materials such as resins and other fluids used inhistological tissue processing are also contemplated in the aboveexamples, and prior art tissue processor 10 is not intended to belimited to the infiltrating materials mentioned herein. It is alsocontemplated that infiltrating material may be mixture of substances,such as mineral oils and paraffin wax.

Improvements in Reagent Management

The prior art tissue processor 10 disclosed in WO 03/02984 and asdescribed herein can be operated by a reagent management system thatcontrols reagent use for optimal tissue processing results. An exemplaryreagent management system and method of managing resources of ahistological issue processor, such as the prior art tissue processor 10,is described in International PCT Application No. PCT/AU2004/001337,publication No. WO 2005/031312, titled “System and Method forHistological Tissue Specimen Processing”, published on 7 Apr. 2005 andfiled by Vision Biosystems Limited.

The reagent management system can include a concentration managementmodule that preferably uses a calculation method to determine reagentconcentration at each station/bottle of a tissue processor, such asprior art tissue processor 10. The calculation method involves using aninitial station concentration, which may be set to the reagent's defaultvalue, and tracking station use to calculate an estimate of the currentconcentration of the reagent. Tracking station use can includecalculating an estimate of reagent carry over from the retort walls,baskets and biopsy pads used by the tissue processor. The reagentmanagement system then operates the tissue processor based on thecalculated reagent station concentration level.

The present invention provides improvements in reagent management byproviding a tissue processor 100 that includes at least one sensor 74,76 for measuring a measured purity level of a reagent. Ideally, themeasured purity level is a concentration value of the reagent derivedfrom a measured parameter value. The present invention further providesmethod of operating the tissue processor 100, which may becomputer-implemented by a computer program product, and a controller 25of the tissue processor 100 that is configured to perform the method.

In contrast to the reagent management system of WO 2005/031312 and asdescribed above, the inventive tissue processor 100 with controller 25and method of operating the tissue processor 100 can measure the actualreagent concentration, by means of the at least one sensor 74, 76,before or during operation of the tissue processor 100 to perform atissue processing protocol. Accordingly, the reagent management systemcan control reagent use on the basis of the measured reagentconcentration values instead of calculated reagent concentration valuesbased on an estimate of reagent carry over. The present inventiontherefore provides greater racy and reliability in measuring reagentconcentration due to the at least one sensor 74, 76. Furthermore, thepresent invention enables the reagent management system to more readilycontrol tissue processor workflows as the reagent quality can bevalidated before or during operation of the tissue processor 100.

For simplicity, the same reference numerals have been used for featuresof the tissue processor 100 according to embodiments of the inventionthat correspond to the same features of the prior art tissue processor10. It is intended that the above description of the prior art tissueprocessor 10 and disclosure of WO 03/029845 is relevant to the featuresof the tissue processor 100 with the same reference numerals. The tissueprocessor 100 can, in some embodiments, include one or more features ofthe prior art tissue processor 10, although not explicitly mentioned inthe following description of preferred embodiments of the invention. Aperson skilled in the art would appreciate how the features of the priorart tissue processor 10 could be implemented with respect to the tissueprocessor 100 according to embodiments of the invention. It should beappreciated, however, that embodiments of the invention are not limitedto having identical components or all of the components of the prior arttissue processor 10 disclosed in WO 03/029845 and as described herein.For example, embodiments of the invention may be directed to tissueprocessors or methods of operating tissue processors that differ fromthe prior art tissue processor 10 and that only comprise a singleretort, as will be described herein.

The tissue processor 100 of the present invention includes at least oneretort or receiving tissue samples, at least one container 26 forstoring a reagent, and at least one sensor 74 arranged for fluidcommunication with one or both of the at least one container 26 and theat least one retort 12 for measuring a measured purity level of areagent.

Embodiments of the tissue processor 100 are illustrated in simplifiedschematic block diagrams as shown in FIGS. 9a-d and 10. The electricalconnections between the sensors 74, 76, manifold 38, reagent valve 40,air pump 44, controller 25, and other elements have been omitted fromthe figures for clarity and are considered as standard fittings known toa person spilled in the art, and understood with reference to the priorart tissue processor 10 as shown in FIGS. 1 to 8.

Referring to FIGS. 9a and 9b , the tissue processor 100 can include areagent line 34 connecting the container 26 and the retort 12. Thesensor 74 can be arranged in the reagent line 34, positioned between thecontainer 26 and retort 12. A valve mechanism 50 can be optionallyincluded in the reagent line 34 to control flow of a reagent between thecontainer 26 and retort 12, depending on the direction of flow during atissue processing protocol. For example, on filling of the retort 12,reagent will be conducted from the container 26 to the retort 12 in thereagent line 34. Conversely, on draining of the retort 12, the directionof flow will be reversed as controlled by the valve mechanism 50. Insome embodiments, the valve mechanism 50 may include the reagent valve40 of the prior art tissue processor 10. The sensor 74 can be positionedin the reagent line 34 between the valve mechanism 50 and, retort 12 orbetween the container 20 and valve mechanism 50, as shown respectivelyin FIGS. 9a and 9b . Preferably, the sensor 74 is positioned between thevalve mechanism 50 and retort 12 as shown in FIG. 9 a.

Alternatively, in the embodiment of FIG. 9c the sensor 74 is arranged ina bypass line 42 that receives a portion of the reagent when the reagentis conducted in the reagent line 34. The bypass line 42 is positionedbetween the optional valve mechanism 50 and the retort 12 as shown inFIG. 9c . However, the bypass line 42 could be positioned between thecontainer 26 and the optional valve mechanism 50. Further, in otherembodiments the bypass line 42 could connect to the reagent line 34 oneither side of the valve mechanism 50. Entry of reagent to the bypassline 42 from the reagent line 34 could also be valved to selectivelycontrol the amount of reagent that is conducted to the sensor 74 (notshown).

FIG. 9d illustrates another alternative embodiment of the tissueprocessor 100 in which the sensor 74 is arranged in a dedicated line 36that is connected to the container 26 and/or retort 12. The dedicatedline 36 is shown in broken lines to illustrate that the dedicated line36 could be fluidly connected to one or both of the container 26 andretort 12. Reagent can be conducted from one of the container 26 orretort 12 in the dedicated line 6 to the sensor 74 for measuring themeasured purity level of the reagent. In this regard, an air line 30 maybe connected from the air pump 44 to the sensor 74 in order to pumpreagent in the dedicated line 36 (not shown).

FIGS. 9a-d illustrates embodiments of the tissue processor 100 thatinclude a single container 26, retort 12 and sensor 74. However, thetissue processor 100 may include a plurality of containers 26 forstoring different reagents and/or the same reagent at differentconcentrations, as shown in FIG. 10.

A preferred embodiment of the tissue processor 100 is illustrated inFIG. 10. The tissue processor 100 can include a plurality of containers26 (six shown, although various numbers of containers can be provided),two retorts 12 and 14 and two sensors 74 and 76. The arrangement issimilar to that shown and described with reference to FIG. 9a in whicheach sensor 74 and 76 is positioned in the reagent line 34 between thereagent valve 40 and retorts 12 and 14. However, in other embodiments asingle sensor 74 could be positioned between the reagent valve 40 andconnecting to both of the retorts 12 and 14 (not shown).

As shown in FIG. 10, the tissue processor 100 can include the reagentvalve 40 for selectively connecting each container 26 to the retorts 12and 14 for conducting reagent therebetween. Further, the tissueprocessor 100 can include four infiltrating baths 16-22 connected to theretorts 12 and 14 by an infiltrating line 32. The infiltrating baths16-22 can include infiltrating material such as paraffin wax for use bythe tissue processor 100 in performing a tissue processing protocol forinfiltrating of tissue samples. The tissue processor 100 can alsoinclude the air pump 44 with air lines 30 and manifold 38, whichtogether with a controller 25 enable transport of various fluids, suchas process fluids or waste, in the tissue processor 100.

The sensors 74 and 76 preferably are fluid sensors configured to measurethe density value of the reagent when conducted thereto from thecontainer(s) 26 or retorts 12 and 14 to the sensors 74 and 76. Thesensors 74 and 76 can be densitometers, and preferably, oscillating pipedensity meters, which include an oscillating element and measure thedamping effect of the reagent flow. Alternatively, the sensors 74 and 76can be oscillating u-tube or “tuning fork” density meters, or otherdensitometers as known to a person skilled in the art. Where the sensors74 and 76 include an oscillating tube, the manifold 38 of the tissueprocessor 100 shown in FIG. 10 is preferably inclined at an angle. Theinclination is such that any air bubbles from the oscillating tube ofthe sensor 74, 76 can be removed, thereby allowing density measurementsto be taken during filling of the retorts 12 and 14, which occur whenconducting reagent from the container(s) 26 to the retorts 12 and 14.

Ideally, the sensors 74 and 76 provide minimal fluidic restriction onthe fluid/reagent flow in the tissue processor 100. For example, thesensors 74 and 76 may have large internal tube diameter that minimisefluidic restriction. This is particularly important when the sensors 74and 76 are positioned in the reagent line 34 (see FIGS. 9a-b and 10),for which such restriction may impact on fill and drain times betweenthe container(s) 26 and retorts 12 and 14.

Referring now to FIG. 11, the present invention provides a method ofoperating the tissue processor 100 for processing tissue samples. FIG.11 is a flow chart of the steps 80-86 of the method of the invention.The method includes at step 80, conducting reagent from the at least onecontainer 26 or the at least one retort 12 to the at least one sensor74. At step 82, the method further includes automatically measuring, bymeans of the at least one sensor 74, the measured purity level of thereagent. At step 84, the method further includes checking whether themeasured purity level meets a predetermined purity level of the reagentassociated with the at least one container 26. The method furtherincludes at step 86 automatically determining, based on a result ofchecking, whether the reagent is suitable for processing tissue samplesin the tissue processor 100.

The predetermined purity level of the reagent can be associated with theat least one container 26 by means of data or information of the reagentthat is intended to be stored in the container 26. For example, thecontainer 26 may include an identifier for a specific reagent that ispositioned on the physical container 26, such as through use of a label.The identifier may be machine-readable and include a Radio FrequencyIdentification Device (RFID). The identifier can include informationsuch as the type and/or concentration of the reagent that is to bestored in the container 26.

In some embodiments, the method further includes the step of providingthe predetermined purity level of the reagent based on reagent data forthe at least one container 26. The reagent data for the at least onecontainer 26 is preferably provided by a user or operator of the tissueprocessor 100. The tissue processor 100 can further include an inputdevice such as control interface 24, which can include the controlinterface 24 shown in FIGS. 3 and 8 of the prior art tissue processor10. The control interface 24 can employ a graphical user interface, andmay include a touchscreen display, keyboard and/or mouse, operable by auser to provide the reagent data. The control interface 24 can connectedto a controller 25 of the tissue processor 100, which is configured toreceive the reagent data from the control interface 24.

Additionally/alternatively, the tissue processor 100 can include acontroller 25, which can include the controller 25 shown in FIG. 8 ofthe prior art tissue processor 10. The controller 25 can be configuredto receive the reagent data from a server or computing system, such asthrough a wireless or hard-wired connection. The controller 25 may belocated on the tissue processor 100 in a cabinet 11 as shown in FIG. 3of the prior art tissue processor 10, or may be part of a stand-alonecomputer that communicates with the tissue processor 100. The controller25 may include a personal computer processor such as a Celeron chip byIntel Corporation located on an ETX form factor PCB (not shown). Thecontroller 25 may contain or store a number of predefined protocols (orsteps) for processing tissue, the protocols being stored in anon-volatile memory such as a hard drive. Protocols may be programmableby the user to implement a number of steps for tissue processing, orthey may be predefined. Typical protocol parameters include whichreagents are to be applied to the samples, how long the reagents are tobe applied, the temperature at which the reagents are applied, whetheragitation is to take place, and whether ambient pressure in the retort12, 14 is to be changed.

The reagent data preferably includes at least a concentration value ofthe reagent for the at least one container 26. The user may provide theconcentration value, using the control interface 24 or controller 25 asa percentage dilution of the reagent in water, such as 70%, 80% or 100%,or provide a concentration in Molar (M), g/L, mg/mL, to name a few. Thereagent data can also include one or more of a reagent type, a reagentname and a container number for the tissue processor 100. For example,the reagent type can include a dehydrating fluid, such as ethanol,methanol, isopropanol, butanol, ethylene glycol, and various alcohols, aclearing reagent, such as xylene, di-pentene, D-limonene, 1,1,1,frichloroethane, toluene and dioxane, and an infiltrating material, suchas paraffin wax, to name a few.

In preferred embodiments of the invention, the predetermined puritylevel of the reagent is a concentration level determined based on theconcentration value from the reagent data. The concentration level caninclude one of a threshold value or a tolerance range of values. Thethreshold value can be the concentration value of the reagent includedin the reagent data from the user. Where the concentration level is atolerance range of values, the range can be determined based on theconcentration value included in the reagent data. The method may includedetermining the tolerance range depending on the reagent type, such asdehydrating fluid, clearing reagent or infiltrating material, and insome embodiments, through a calculation based on the pure reagentconcentration or using a look-up table for the reagent. For example, asmaller tolerance range may be required for reagents in which avariation in concentration level will detrimentally affect the qualityof the processed tissue samples.

In some embodiments, the method further includes repeating the measuringstep 82 one or more times, preferably three times, and calculating anaverage of the measured values of a parameter that represents themeasured purity level of the reagent. In this case, the calculatedaverage represents the measured purity level of the reagent. Themeasuring step 82 may include measuring density values of the reagentusing the at least one sensor 74, 76, which may be a fluid sensor ordensitometer, and thus the calculated average can include an averagedensity value for the reagent. The method may further include a step ofderiving from the measured density value or the average of the measureddensity values, a concentration value of the reagent. The step ofdenying the concentration value may include performing a calculationmethod based on using a look-up table for the pure reagent. The measuredpurity level of the reagent determined at measuring step 82 preferablyincludes the derived concentration value.

Accordingly, the checking step 84 of FIG. 11 is preferably performed onthe basis of a comparison of concentration values. Ideally, the measuredpurity level is the concentration value derived from the measureddensity value or average of measured density values, and thepredetermined purity level is the concentration level, being thethreshold value or tolerance range of values determined based on theconcentration value from the reagent data. The checking step 84 caninclude checking whether the measured purity level is (i) greater thanthe threshold value of the predetermined concentration level, or (ii)within the tolerance range of values of the predetermined concentrationlevel.

In alternative embodiments, the predetermined purity level can be adensity level determined based the concentration value from the reagentdata. The density level can be a threshold value, where the thresholdvalue can be a density value derived from the concentration value fromthe reagent data, such as through a calculation based on the purereagent concentration or using a look-up table for the reagent. Wherethe density level is a tolerance range of values, the range can bedetermined based on the derived density value. Furthermore, the measuredpurity level of the reagent can be the measured density value or averageof measured density values. Thus, in alternative embodiments, thechecking step 84 of FIG. 11 is performed on the basis of a comparison ofdensity values.

In some embodiments, the determining step 86 of FIG. 11 includesdetermining that the reagent is suitable for processing tissue sampleswhen the measured purity level is greater than the threshold value orwithin the tolerance range of values. Step 86 further includesdetermining that the reagent is unsuitable for processing tissue sampleswhen the measured purity level is less than the threshold value or fallsoutside the tolerance range of values. When the reagent is determined tobe unsuitable for processing tissue samples, the method can furtherinclude the step of flagging the at least one container 26 for non-useby the tissue processor 100. The method can also further include thestep of generating, at the tissue processor 100, a notification signalfor a user to check the reagent in the flagged container 26. Thenotification signal can be provided to the user by the input device,such as a control interface 24 having a user display. The notificationsignal can include a message and/or alarm displayed on the controlinterface 24 or user display.

The method can be performed prior to operating the tissue processor 100to perform a tissue processing protocol using the reagent. This methodrequires a dedicated tissue processor workflow to check the measuredpurity level of the reagent prior to use in a tissue processing protocolby the tissue processor 100. Referring to FIG. 9 d, the tissue processor100 includes a dedicated line 36 connecting the container 26 or theretort 12 to the sensor 74. The dedicated line 36 is separate from thereagent line that connects the container 26 and retort 12. In someembodiments, the method includes at step 80, conducting reagent in thededicated line 36 from the container 26 or the to retort 12 to thesensor 74.

The dedicated tissue processor workflow requires a specific action tofill and drain reagent to the dedicated line 36 to measure the puritylevel or concentrate of the reagent. For example, reagent can be storedin the container 26 and conducted to the sensor 74 in order to screenthe reagent and check its purity level or concentration prior to use bythe tissue processor 100. If the method determines at step 86 that thereagent is unsuitable for use, the container 26 associated with thereagent, i.e. the container 26 for storing the reagent, can be flaggedfor non-use. The “flagging” may be software-implemented in a reagentmanagement system that locks-out the container 26 for use in tissueprocessing protocols. The “flagging” may result in selection by thereagent management system of an alternative container 26 for use in atissue processing protocol. Furthermore, the method can includegenerating a notification signal for a user to check the reagent in theflagged container 26. The notification signal can be a message and/oralarm displayed on the control interface 24 or user display.

In another example, reagent can be stored in the retort 12 and conductedto the sensor 74 in order to screen the reagent and check its puritylevel or concentration prior to conducting the reagent to its associatedcontainer 26. If the method determines at step 86 that the reagent isunsuitable for use, the container 26 associated with the reagent, e.g.in this case the container 26 storing the reagent, can be flagged fornon-use as above, and further, the reagent can be conducted to wasteline of the tissue processor 100 for removal therefrom so as to notcontaminate or dilute any reagent currently in the associated container26.

In other embodiments, the method is preferably performed when operatingthe tissue processor 100 to perform a tissue processing protocol usingthe reagent. This method can be implemented in two ways, (i) adapting atissue processor workflow for a tissue processing protocol to check thereagent during use (e.g. filling/draining of the retort 12, 14) by thetissue processor 100, and (ii) a monitoring tissue processor workflowfor calculating contamination of the reagent from successive uses intissue processing protocols. Advantageously, the adapted workflow andmonitoring workflow minimises inefficiency in operation of the tissueprocessor 100 as it avoids additional checks and retort cleans that arerequired to perform the dedicated workflow described above.

Referring to FIGS. 9a-c and 10, the tissue processor 100 can include areagent line 34 connecting the at least one container 26 and the atleast one retort 12, 14. The at least one sensor 74, 76 is arranged influid communication with the reagent line 34. The sensor 74, 76 can bepositioned in the reagent line 34 as shown in FIGS. 9a-b and 10, oralternatively, positioned in a bypass line 42 that receives a portion ofthe reagent when the reagent is conducted in the reagent line 34 asshown in FIG. 9c . With these embodiments of the tissue processor 100,the method can be performed on filling of the retort 12, 14 with reagentat the start of a tissue processing protocol and/or on draining of theretort 12, 14 to remove reagent at the end of a tissue processingprotocol, since the reagent from reagent line 34 conducted between thecontainer 26 and retorts 12 and 14, will pass through the sensor 74, 76positioned in the reagent line 34 or bypass line 42.

For the adapted tissue processor workflow, the method further includesthe step of operating the tissue processor 100 to stop filling ordraining of the at least one retort 12, 14 to perform at least methodsteps 82-86 of FIG. 11. On filling of the retort 12, 14, the method caninclude operating the tissue processor 100 to stop filling priorcontacting tissue samples stored in the at least one retort 12, 14. Ondraining of the retort 12, 14, the method can include operating thetissue processor 100 to stop filling prior to reagent being delivered tothe at least one container 28 associated with the reagent. The stoppingstep advantageously enables the reagent purity level or concentration tobe checked prior to potentially contaminating and/or destroying tissuesamples on filling and then processing in the retort 12, 14, and priorto potentially contaminating and/or diluting any reagent in theassociated container 26 on draining of the reagent from the retort 12,14. This desirably enables the reagent quality to be verified before orduring operation of the tissue processor to perform a tissue processingprotocol using the reagent, which can thereby avoid user error andpotential suboptimal tissue processing of the tissue samples.

When the reagent is determined to be suitable for processing tissuesamples at step 86 of FIG. 11, the method can further include the stepof operating the tissue processor 100 to continue filling or draining ofthe retort 12, 14 to complete the tissue processing protocol. Otherwise,when the reagent is determined to be unsuitable for processing tissuesamples, the method can further include the step of operating the tissueprocessor 100 to abandon the tissue processing protocol.

The adapted tissue processor workflow filling of the retort 12, 14 isillustrated in a preferred embodiment of the invention as shown in theflow charts of FIGS. 12 and 13 a-c. FIG. 12 is a simplified flow chartof a workflow for reagent screening (i.e., checking reagent puritylevel, particularly concentration) on retort filling that incorporatesthe method of FIG. 11 and embodiments as described herein. The flowchart begins with slowly filling the retort 12, 14 with reagent from acontainer 26. Preferably, the retort is filled for 10 seconds and thetissue processor 100 is operated to stop filling prior to reagentcontacting tissue samples stored in the retort 12, 14. The next step inthe workflow is to wait for a stable reading from the density meter 74,76. Next, the reading from the density meter 74, 76 is checked, whichinvolves performing method steps 82 and 84. The workflow next determinesif the reading is good, which involves performing method step 88. If thereading is good, the retort 12, 14 is continued to be filled with thereagent and the processing protocol is completed. Otherwise, thecontainer 26 associated with the reagent is locked-out for use by thetissue processor 100 and an alternatively bottle/container 26 (inembodiments with a plurality of containers 26) is selected for use inthe tissue processing protocol. The user is notified regarding thelocked-out or flagged container 26, such as by the control interface 24,and the option to use an alternative bottle/container 26. The workflowthen abandons the tissue processing protocol and waits for the user totake further action, e.g. replace the reagent in the flagged container26 or select the alternative bottle/container 26.

Referring to FIGS. 13a -c, more detailed flow charts of the workflow forreagent screening shown in FIG. 12 and described above are provided. Inparticular, FIG. 13a shows additional steps in the workflow which checksif the density meter(s) 74, 76 is enabled by the tissue processor 100,and otherwise logs a DM Fault (125). Once the density meters 74, 76 areenabled, the reagent valves (such as ret1-vrgt and ret2-vrgt from FIG. 2of the prior art tissue processor 10) are opened for filling of theretort 12, 14 with reagent. FIG. 13b shows detail of the stopping offilling of the retort 12, 14 in order to take the density measurementand check the reagent purity level or concentration. The stopping can beachieved by implementing a “Paused” function in the tissue processorworkflow as shown in FIG. 13b , which pauses the tissue processingprotocol and filling of the retort 12, 14 for a time period until thedensity measurement is performed and reagent purity level orconcentration checked. FIG. 13c shows detail of the method steps 82-86being performed, in which three stable density readings are taken andthe density meter (DM) reading (e.g. an average of the three densitymeasurements) is checked to see if it matches the expected reagentdensity (e.g. predetermined value based on reagent data from user) towithin an error or tolerance. If the DM reading does not match to withinthe error or tolerance, the workflow logs a Reagent not in expectedDensity Reagent Error (121), flags the bottle 26 against reuse, closesthe reagent valves and returns “Retry New Reagent”. This may involve anotification signal or message being generated for the user to view andtake appropriate action, such as selecting an alternativebottle/container 26 or replacing the reagent in the container 26.

The adapted tissue processor workflow as described above can beimplemented in a monitoring tissue processor workflow performed by thereagent management system. The monitoring tissue processor workflowincludes performing the adapted tissue processor workflow one or moretimes, and preferably on both filling and draining of the retort 12, 14during a tissue processing protocol performed by the tissue processor100. This enables the reagent purity level or concentration to bevalidated before and after use of the reagent in a tissue processingprotocol. Ideally, the monitoring tissue processor workflow performs theadapted tissue processor workflow each time a tissue processing protocolis performed by the tissue processor 100, which enables data of thereagent purity level or concentration to be collected on successive usesof the reagent by the tissue processor 100.

In some embodiments, the tissue processor 100 it eludes a firstcontainer for storing a first reagent and a second con oiler for storinga second reagent. The first and second containers may include reagentcontainers 26 as shown in FIGS. 9a-d and 10. However, the firstcontainer may include an infiltrating bath 16-22 or alternativecontainer of the tissue processor 100 that stores a reagent or treatmentfluid used by the tissue processor 100 to treat tissue samples in theretort 12, 14.

For the monitoring tissue processor workflow, the method can furtherinclude the step of operating the tissue processor 100 to perform atissue processing protocol using the first reagent and the secondreagent. Preferably, the first reagent is used in the tissue processingprotocol prior to the second reagent being used. The tissue processingprotocol can include treating tissue samples in the retort 12, 14 withthe first reagent by conducting or pumping the first reagent to and/orfrom the first container to the retort 12, 14 on filling and/or drainingof the retort 12, 14. Ideally, the tissue processing protocol thenincludes the same steps of treating the tissue samples in the retort 12,14 with the second reagent.

Advantageously, the method for the monitoring tissue processor workflowcan include automatically determining a carry over volume of the firstreagent from the first container into the second reagent from the secondcontainer. The carryover volume can be determined by firstly, providingan initial volume of the second reagent in the second container, whichcan be provided by the user via the input device 24 or controller 25.Then the method includes performing the measuring step 82 to measure,using the sensor 74, 76, a density value of the first reagent ondraining of the retort 12, 14 and a density value of the second reagenton filling and draining of the retort 12, 14. The carry over volume canthen be calculated automatically according to:

$V_{CO} = {\frac{\rho_{C\; 2_{out}} - \rho_{C\; 2_{in}}}{\rho_{C\; 1_{out}} - \rho_{C\; 2_{out}}} \times V}$

wherein: V_(CO)=volume of carry over (L), ρ_(C2) _(out) =measureddensity value of the second reagent on draining of the at least oneretort (kg/m³), ρ_(C2) _(in) =measured density value of the secondreagent on filling of the at least one retort (kg/m³), ρ_(C1) _(out)=measured density value of the first reagent on draining of the at leastone retort (kg/m³), and V=initial volume of the second reagent in thesecond container (L).

The carry over volume is representative of the volume of the firstreagent that has contaminated the second reagent during successive usesby the tissue processor 100. This information can be used by the reagentmanagement system to control use of reagents by the tissue processor100, such as by selecting the specific reagents and their order of usein a tissue processing protocol. Further, the carry over volume can beused by the reagent management system to estimate the contaminationlevels of reagents/treatment fluids from other containers, such as theinfiltrating baths 16-22. This is particularly advantageous as thepurity level or concentration of the infiltrating fluids such asparaffin wax from the infiltrating baths 16-22 is not measured by thesensor 74, 76 of the tissue processor 100. Accordingly, this method ofcalculating the carry over volume using actual measured reagentconcentration provides accuracy in the calculation of the purity levelor concentration of infiltrating fluids or other fluids by the reagentmanagement system.

The present invention also provides a tissue processor 100 that includesat least one retort 12 for receiving tissue samples, at least onecontainer 26 for storing a reagent and at least one sensor 74 arrangedfor fluid communication with one or both of the at least one container26 and the at least one retort 12 for measuring a measured purity levelof a reagent. The measured purity level is preferably a concentrationvalue derived from a measured parameter value. The tissue processor 100also includes a controller 25 configured to perform the method ofoperating a tissue processor according to steps 80-86 of FIG. 11.

In preferred embodiments of the invention, the controller 25 is alsoconfigured to perform any of the additional method steps described aboveand with reference to FIGS. 11, 12 and 13 a-c. Accordingly, the methodof operating the tissue processor 100 can be implemented through thecontroller 25 and further in software, firmware and/or hardware invariety of manners as would be understood by a person skilled in theart.

The present invention also provides a computer program product includinga computer readable medium having computer readable program code andcomputer readable system code embodied on the medium for, operating atissue processor (such as tissue processor 100), within a dataprocessing system, where the computer program product includes computerreadable code within the computer readable medium for performing themethod of operating a tissue processor according to steps 80-86 of FIG.11.

In preferred embodiments of the invention, the computer readable codecan perform any of the additional method steps described above and withreference to FIGS. 11, 12 and 13 a-c. Accordingly, the method ofoperating the tissue processor 100 can be implemented through thecomputer program product in software. The computer program code could besupplied in a number of ways, for example on a memory of the tissueprocessor 100, or on a tangible computer readable medium, orcommunicated as a data signal or file for the tissue processor 100.

The inventive method, tissue processor and computer program product asdescribed herein advantageously enable reagent quality to be verifiedbefore or during operation of a tissue processor to perform a tissueprocessing protocol with the reagent. The inventive tissue processorincludes at least one sensor for measuring measured purity level of thereagent, which is preferably a concentration value derived from themeasured parameter value. Accordingly, the actual reagent concentrationlevel can be determined, by means of the at least one sensor, before orduring operation of the tissue processor 100 to perform the tissueprocessing protocol. The determined reagent concentration level can beused by a reagent management system to more readily control reagent useand tissue processor workflows for performing tissue processingprotocols. The invention can therefore improve the likelihood ofsuccessful tissue processing by avoiding user error potential suboptimaltissue processing through verifying reagent quality.

Improvements in Basket Design

The present invention also provides improvements in cassette basketdesign for tissue processors.

Referring to FIGS. 4 to 6, the retort 12 of the prior art tissueprocessor 10 includes three fluid level sensors 52 for detecting thelevel of process fluid, such as reagents, in the retort 12. The fluidlevel sensors 52 are positioned at different heights of the retort 12 asbest shown in FIG. 6. Multiple baskets 62 are configured to beaccommodated and stacked the retort 12 as shown in FIG. 5. The baskets62 are sufficiently sized for positioning within the retort 12 and tomaximise the volume capacity for storing tissue samples, which may bestored in the baskets 62 within cassettes. The prior art baskets 62 areusually made of a metallic material, and thus provide a reflectivestructure when exposed to light. Since the fluid level sensors 52 aretypically optical sensors, the metallic reflective structure caninterfere with the optical sensors for use in determining the level ofthe process fluid.

The present invention provides a container 110 for storing tissuesamples for processing in a tissue processor (such as the prior arttissue processor 10 or inventive tissue processor 100). The container110 is configured to be accommodated in a retort 12, 14 of the tissueprocessor 10, 100 and provide access the stored tissue samples forprocessing with a process fluid in the retort 12, 14. The retort 12, 14includes at least one sensor 52 for detecting a level of the processfluid in the retort 12, 14. The container 110 is configured to minimiseinterference with the at least one sensor 52.

FIGS. 14a-b and 15a-b illustrate a container 110 for storing tissuesamples for processing in a tissue processor according to a preferredembodiment of the invention. The container 110 can be sufficiently sizedfor positioning within a retort 12, 14. Furthermore, the container 110can be a basket, as shown in FIGS. 14a-b and 15a-b or have a nettedstructure in order to provide fluid access to the stored tissue samplesfor processing.

In some embodiments, the at least one sensor 52 is an optical sensor,and the container 110 includes at least one non-reflective surface forminimising interference with the optical sensor 2 (not shown). Thenon-reflective surface preferably includes an opaque material order tominimise reflections that can occur during use of the optical sensor 52(not shown). In other embodiments, the sensor 52 can be other sensorsthat are affected by interference from surface reflections as known to aperson skilled in the art.

The container 110 can be configured to releasably receive one or moreclips having the at least one non-reflective surface (not shown). Wherethe container 110 is a basket, as shown in FIGS. 14a-b and 15a -b, theone or more clips can releasably attach to openings in side portions ofthe basket 110 (not shown). The side portions can include the foursurfaces of the receptacle 60 of the basket 110 that exclude baseportion 63. Additionally/alternatively, the side portions of thecontainer or basket 110 can each include the non-reflective surface,which may be integral with the container 110 (not shown). The sideportions are preferably formed of a non-reflective or opaque material inthese embodiments.

The present invention also provides a container 114 for storing tissuesamples for processing in a tissue processor 10, 100 that includes aretractable handle 65 to facilitate stacking of plurality of thecontainers 110.

FIGS. 14a-b and 15a-b illustrate the container 110 for storing tissuesamples according to a preferred embodiment of the invention, showingthe retractable handle 65. FIGS. 14a-b show the handle 65 in theretracted position and FIGS. 15a-b show the handle 65 in the extendedposition. The container 110 can be sufficiently sized for positioningwithin a retort 12, 14 and be a basket or have a netted structure inorder to provide fluid access to the stored samples for tissueprocessing. The container or basket 110 as illustrated includes areceptacle 60 and lid 64. As best shown in FIG. 15b , the receptacle 60can include a central recess 66 for receiving the handle 65 in theretracted position. The central recess 66 forms a longitudinal slot forreceiving arms of the handle 65 at opposite ends of the slot in theretracted position.

Preferably, the handle 65 is integral with the receptacle 60 as shown inFIGS. 14a-b and 15a -b. In particular, FIG. 15b illustrates that thereceptacle 60 can include brackets at opposite ends of the longitudinalslot 66 for receiving, in an opening of the bracket, each arm of thehandle 65. The handle 65 is extended and retracted by manually pushingand pulling the handle 65 with respect to the receptacle 60 so as tomove the arms of the handle 65 relative to the openings of the brackets.Integrating the handle 65 into the receptacle 60 can avoid anydependency on secure attachment of a lid 64, thereby reducing the riskof dropping the container 110 and/or tissue samples during transport.

Referring to FIG. 14a , the container or basket 110 can further includea lid 64 having a slot 61 through which the handle is extendable to theextended position shown in FIG. 15 a. The slot 61 can be a longitudinalslot which is slightly longer than a length of the handle 65 in order toallow the handle 65 to pass through to the extended position whileminimising the gap therebetween through which tissue samples could exitthe receptacle 60. The slot 61 is centrally positioned as shown in FIGS.14a and 15a for stability of the container 110 when carried by thehandle 65. The slot 61 can also be shaped to include a wider portion ina centre part of the lid 64 for receiving a curved portion of the handle65.

Referring to FIG. 14b , the receptacle 60 can include a base portion 63having a slot 69 in a central portion thereof. The slot 69 is sized forreceiving at least part of a handle 65 of a corresponding container orbasket 110. For example, as shown in FIG. 14a , part of the handle 65may protrude through the slot 61 of the lid 64, particularly in thecentre part of the lid 64, in the retracted position. The slot 69 of thereceptacle 60 can receive the protruding part of the handle 85 tofacilitate stacking of plurality of the containers 110. Thisadvantageously enables the base portion 63 and lid 64 to sitsubstantially flush when a plurality of containers 110 are verticallystacked.

The container 110 can also include an electronic identifier 79 for usein tracking the location of the container 110 during sample processing.The electronic identifier 79 can include a barcode, or more preferably,a Radio Frequency Identification Device (RFID) tag as shown in FIGS.14a-b and 15a -b. In some embodiments, the electronic identifier 79 isprovided on a tag 78 which is attached to the receptacle 60 of thebasket 110. Preferably, the tag 76 is attached to a side portion of thereceptacle 60 (excluding the base portion 63) so as to minimiseinterference with the handle 65 and can be easily read when a pluralityof containers 110 are vertically stacked.

Advantageously, the inventive container 110 for storing tissue samplesminimises interference with fluid sensors 52 of the tissue processor 10,100, such as by preferably providing at least one non-reflectivesurface. Furthermore, the inventive container 110 provides a retractablehandle so that a plurality of containers 110 can be readily stacked fortransport or use in the tissue processor 10, 100.

Additional non-limiting exemplary embodiments of the disclosure are setforth below.

Embodiment 1: A method of operating a tissue processor for processingtissue samples, the tissue processor including: at least one retort forreceiving tissue samples; at least one container for storing a reagent;and at least one sensor arranged for fluid communication with one orboth of the at least one container and the at least one retort formeasuring a measured purity level of a reagent, the method including thesteps of: a) conducting reagent from the at least one container or theat least one retort to the at least one sensor: b) automaticallymeasuring, by means of the at least one sensor, a measured purity levelof the reagent; c) checking whether the measured purity level meets apredetermined purity level of the reagent associated with the at leastone container; and d) automatically determining, based on a result ofthe checking, whether the reagent is suitable for processing tissuesamples in the tissue processor.

Embodiment 2: The method according to Embodiment 1, further includingthe step of: providing the predetermined purity level of the reagentbased on reagent data for the at least one container.

Embodiment 3: The method according to Embodiment 2, further includingthe step of: receiving, at the tissue processor, the reagent data forthe at least one container from a user.

Embodiment 4: The method according to Embodiment 3, wherein the tissueprocessor further includes an input device, and the receiving stepincludes receiving the reagent data by means of the input device.

Embodiment 5: The method according to any one of Embodiments 2 to 4,wherein the reagent data includes at least a concentration value of thereagent.

Embodiment 6: The method according to Embodiment 5, wherein thepredetermined purity level of the reagent is a concentration leveldetermined based on the concentration value from the reagent data.

Embodiment 7: The method according to Embodiment 6, wherein theconcentration level is one of: a threshold value, wherein the thresholdvalue is the concentration value from the reagent data; or a tolerancerange of values determined based on the concentration value from thereagent data.

Embodiment 8: The method according to any one of Embodiments 1 to 7,wherein the at least one senor measures at step b) a density e thatrepresents the measured purity level of the reagent.

Embodiment 9: The method according to Embodiment 8, further includingthe steps of: repeating the measuring step b) one or more times; andcalculating an average of the measured density values, wherein thecalculated average represents the measured purity level of the reagent.

Embodiment 10: The method according to Embodiment 9, wherein themeasured purity level is a concentration value derived from the measureddensity value or the average of the measured density values.

Embodiment 11: The method according to any one of Embodiments 7 to 10when Embodiment 8 includes the method according to Embodiment 7, whereinthe checking step c) includes checking whether the measured purity levelis (i) greater than the threshold value, or (ii) within the tolerancerange of values.

Embodiment 12: The method according to Embodiment 11, wherein theautomatically determining step d) includes: determining that the reagentis suitable for processing tissue samples when the measured purity levelis greater than the threshold value or within the tolerance range ofvalues; and determining that the reagent is unsuitable for processingtissue samples when the measured purity level is less than the thresholdvalue or falls outside the tolerance range of values.

Embodiment 13: The method, according to any one of Embodiments 1 to 12,wherein when the reagent is determined to be unsuitable for processingtissue samples the method further includes the step of: flagging the atleast one container for non-use by the tissue processor.

Embodiment 14: The method according to Embodiment 13, further includingthe step of: generating, at the tissue processor, a notification signalfor a user to check the reagent in the flagged container.

Embodiment 15: The method according to any one of Embodiments 1 to 14,which is performed prior to operating the tissue processor to perform atissue processing protocol using the reagent.

Embodiment 16: The method according to any one of Embodiments 1 to 15,wherein the tissue processor includes a dedicated line connecting the atleast one container or the at least one retort to the at least onesensor, and wherein the conducting step includes conducting reagent inthe dedicated line from the at least one container or the at least oneretort to the at least one sensor.

Embodiment 17: The method according to any one of Embodiments 1 to 14,which is performed when operating the tissue processor to perform atissue processing protocol using the reagent.

Embodiment 18: The method according to any one of Embodiments 1 to 14and 17, wherein the tissue processor includes a reagent line connectingthe at least one container and the at least one retort, wherein the, atleast one sensor is arranged for fluid communication with the reagentline, and wherein the conducting step a) includes conducting reagent inthe reagent line between the at least one container and the at least oneretort.

Embodiment 19: The method according to Embodiment 18, wherein the atleast one sensor is one of: positioned in the reagent line; orpositioned in a bypass line that receives a portion of the reagent whenthe reagent is conducted in the reagent line.

Embodiment 20: The method according to any one of Embodiments 1 to 14and 17 to 19, which is performed on one or both of: filling of the atleast one retort with reagent; and draining of the at least one retortto remove reagent.

Embodiment 21: The method according to Embodiment 20, further includingthe step of: operating the tissue processor to stop filling or drainingof the at least one retort to perform at least steps (b)-(d).

Embodiment 22: The method according to Embodiment 21, wherein operatingthe tissue processor to stop filling or draining includes one or bothof: operating the tissue processor to stop filling prior to reagentcontacting tissue samples stored in the at least one retort; andoperating the tissue processor to stop filling prior to reagent beingdelivered to the at least one container.

Embodiment 23: The method according to Embodiment 21 or Embodiment 22,wherein when the reagent is determined to be suitable for processingtissue samples, the method further includes the step of: operating thetissue processor to continue filling or draining the at least one retortto complete the tissue processing protocol.

Embodiment 24: The method according to any one of Embodiments 21 to 23,wherein when the reagent is determined to be unsuitable for processingtissue samples, the method further includes the step of: operating thetissue processor to abandon the tissue processing protocol.

Embodiment 25: The method according to any one of Embodiments 1 to 14and 17 to 24, wherein the tissue processor includes a first containerfor storing a first reagent and a second container for storing a secondreagent, and wherein the method further includes the steps of: operatingthe tissue processor to perform a tissue processing protocol using thefirst reagent and the second reagent: and automatically determining acarry over volume of the first reagent from the first container into thesecond reagent from the second container.

Embodiment 26: The method according to Embodiment 25, whereinautomatically determining the carry over volume includes the steps of:providing an initial volume of the second reagent in the secondcontainer; and performing the measuring step b) to measure thefollowing: a density value of the first reagent on draining of the atleast one retort; a density value of the second reagent on filling ofthe at least one retort; and a density value of the second reagent ondraining of the at least one retort, wherein the carry over volume iscalculated according to:

$V_{CO} = {\frac{\rho_{C\; 2_{out}} - \rho_{C\; 2_{in}}}{\rho_{C\; 1_{out}} - \rho_{C\; 2_{out}}} \times V}$

wherein: V_(CO)=volume of carry over (L), ρ_(C2) _(out) =measureddensity value of the second reagent on draining of the at least oneretort (kg/m³), ρ_(C2) _(in) =measured density value of the secondreagent on filling of the at least one retort (kg/m³), ρ_(C1) _(out)=measured density value of the first reagent on draining of the at leastone retort (kg/m³) and V=initial volume of the second reagent in thesecond container (L).

Embodiment 27: A computer program product including: computer readablemedium having computer readable program code and computer readablesystem code embodied on the medium for, operating a tissue processor,within a data processing system, the computer program product including:computer readable code within the computer readable medium forperforming the method steps of any one of Embodiments 1 to 26.

Embodiment 28: A tissue processor for processing tissue samples,including: at least one retort for receiving tissue samples; at leastone container for storing a reagent; at least one sensor arranged forfluid communication with one or both of the at least one container andthe at least one retort for measuring a measured purity level of areagent; and a controller configured to: conduct reagent from the atleast one container or the at least one retort to the at least onesensor; measure, by means of the at least one sensor, a measured puritylevel of the reagent; check whether the measured purity level meets apredetermined purity level of the reagent associated with the at leastone container, and determine, based on a result of the checking, whetherthe reagent is suitable for processing tissue samples in the tissueprocessor.

Embodiment 29: The tissue processor according to Embodiment 28, whereinthe controller is further configured to: provide the predeterminedpurity level of the reagent based on reagent data for the at least onecontainer.

Embodiment 30: The tissue processor according to Embodiment 29, whereine controller is further configured to: receive, at the tissue processor,the reagent data for the at least one container from a user.

Embodiment 31: The tissue processor according to Embodiment 30, furtherincluding an input device, and wherein the controller is configured toreceive the reagent data by means of the input device.

Embodiment 32: The tissue processor according to any one of Embodiments9 to 31, wherein the reagent data includes at least a concentrationvalue of the reagent.

Embodiment 33: The tissue processor according to Embodiment 32, whereinthe predetermined purity level of the reagent is a concentration leveldetermined based on the concentration value from the reagent data.

Embodiment 34: The tissue processor according to Embodiment 33, whereinthe concentration level is one of: a threshold value, wherein thethreshold value is the concentration value; or a tolerance range ofvalues determined based on the concentration value.

Embodiment 35: The tissue processor according to any one of Embodiments28 to 34, wherein the at least one sensor measures a density value thatrepresents the measured purity level of the reagent.

Embodiment 36: The tissue processor according to Embodiment 35, whereinthe controller is configured to measure, by means of the at least onesensor, the density value that represents the measured purity level ofthe reagent two or more times, and is further configured to: calculatean average of the measured density values, wherein the calculatedaverage represents the measured purity level of the reagent.

Embodiment 37: The tissue processor according to Embodiment 36, whereinthe measured purity level is a concentration value derived from themeasured density value or the average of the measured density values.

Embodiment 38: The tissue processor according to any one of Embodiments34 to 37 when Embodiment 35 includes the method according to Embodiment34, wherein the controller checks whether the measured purity level is(i) greater than the threshold value or (ii) within the tolerance rangeof values.

Embodiment 39: The tissue processor according to Embodiment 38, whereinthe controller determines that the reagent is suitable for processingtissue samples when the measured purity level is greater than thethreshold value or within the tolerance range of values, and wherein thecontroller determines that the reagent is unsuitable for processingtissue samples when the measured purity level is less than the thresholdvalue or falls outside the tolerance rang of values.

Embodiment 40: The tissue processor according to any one of Embodiments28 to 39, wherein when the reagent is determined to be unsuitable forprocessing tissue samples, the controller is further configured to: flagthe at least one container for non-use by the tissue processor.

Embodiment 41: The tissue processor according to Embodiment 40, whereinthe controller is further configured to: generate, at the tissueprocessor, a notification signal for a user to check the reagent in theflagged container.

Embodiment 42: The tissue processor according to any one of Embodiments28 to 41, wherein the controller determines whether the reagent issuitable for processing tissue samples prior to operating the tissueprocessor to perform a tissue processing protocol using the reagent.

Embodiment 43: The tissue processor according to any one of Embodiments28 to 42, wherein the tissue processor includes a dedicated linecontacting the at least one container or the at least one retort to theat least one sensor, and wherein the controller conducts reagent in thededicated line from the at least one container or the at least oneretort to the at least one sensor.

Embodiment 44: The tissue processor according to any one of Embodiments28 to 41, wherein the controller determines whether the reagent issuitable for processing tissue samples when operating the tissueprocessor to perform a tissue, processing protocol using the reagent.

Embodiment 45: The tissue processor according to any one of Embodiments28 to 41 and 44, wherein the tissue processor includes a reagent lineconnecting the at least one container and the at least one retort,wherein the at least one sensor is arranged for fluid communication withthe reagent line, and wherein the controller conducts reagent in thereagent line between the at least one container and the at least oneretort.

Embodiment 46: The tissue processor according to Embodiment 45, whereinthe at least one sensor is one of: positioned in the reagent line; orpositioned in a bypass line that receives a portion of the reagent whenthe reagent is conducted in the reagent line.

Embodiment 47: The tissue processor according to any one of Embodiments28 to 41 and 44 to 47, wherein the controller determines whether thereagent is suitable for processing tissue samples during one or both offilling of the at least one retort with reagent; and draining, of the atleast one retort to remove reagent.

Embodiment 48: The tissue processor according to Embodiment 47, whereinthe controller is further configured to: operate the tissue processor tostop filling or draining of the at least one retort to determine whetherthe reagent is suitable processing tissue samples,

Embodiment 49: The tissue processor according to Embodiment 48, whereinthe controller operates the tissue processor to stop filling or drainingby one or both of: operating the tissue processor to stop filling priorto reagent contacting tissue samples stored in the at least one retort;and operating the tissue processor to stop filling prior to reagentbeing delivered to the at least one container.

Embodiment 50: The tissue processor according to Embodiment 48 orEmbodiment 49, wherein when the controller determines that the reagentis suitable for processing tissue samples, the controller is furtherconfigured to: operate the tissue processor to continue filling ordraining of the at least one retort to complete the tissue processingprotocol.

Embodiment 51: The tissue processor according to any one of Embodiments48 to 50, wherein when the controller determines that the reagent isunsuitable for processing tissue samples, the controller is furtherconfigured to: operate the tissue processor to abandon the tissueprocessing protocol.

Embodiment 52: The tissue processor according to any one of Embodiments28 to 41 and 44 to 51, wherein the tissue processor includes a firstcontainer for storing a first reagent and a second container for storinga second reagent, and wherein the controller is further configured to:operate the tissue processor to perform a tissue processing protocolusing the first reagent and the second reagent; and determine a carryover volume of the first reagent from the first container into thesecond reagent from the second container.

Embodiment 53: The tissue processor according to Embodiment 52, whereinthe controller is configured to determine the carry over volume by:receiving an initial volume of the second reagent in the secondcontainer; and measuring, by means of the at least one sensor, thefollowing: a density value of the first reagent on draining of the atleast one retort; a density value of the second reagent on filling ofthe at least one retort; and a density value of the second reagent ondraining of the at least one retort, wherein the controller calculatesthe carry over volume according to:

$V_{CO} = {\frac{\rho_{C\; 2_{out}} - \rho_{C\; 2_{in}}}{\rho_{C\; 1_{out}} - \rho_{C\; 2_{out}}} \times V}$

wherein: V_(CO)=volume of carry over (L), ρ_(C2) _(out) =measureddensity value of the second reagent on draining of the at least oneretort (kg/m³), ρ_(C2) _(in) =measured density value of the secondreagent on filling of the at least one retort (kg/m³), ρ_(C1) _(out)=measured density value of the first reagent on draining of the at leastone retort (kg/m³), and V=initial volume of the second reagent in thesecond container (L).

Embodiment 54. A container for storing tissue samples for processing ina tissue processor, wherein the container is configured to beaccommodated in a retort of the tissue processor and provide access tothe stored tissue samples for processing with a process fluid in theretort, wherein the retort includes at least one sensor for detecting alevel of the process fluid in the retort, and wherein the container isconfigured to minimise interference with the at least one sensor.

Embodiment 55: The container according to Embodiment 54, wherein the atleast one sensor is an optical sensor, and the container includes atleast one non-reflective surface for minimising interference with theoptical sensor.

Embodiment 56: The container according to Embodiment 55, wherein thecontainer is configured to releasably receive one or more clips havingthe at least one non-reflective surface.

Embodiment 57: The container according to any one of Embodiments 54 to56, wherein the at least one non-reflective surface includes an opaquematerial.

Embodiment 58: A container for storing tissue samples for processing ina tissue processor, wherein the container is configured to beaccommodated in a retort of the tissue processor and provide access tothe stored tissue samples for processing with a process fluid in theretort, wherein the container includes a retractable handle tofacilitate stacking of a plurality of the containers.

Embodiment 59: The container according to Embodiment 58, furtherincluding a receptacle having a central recess for receiving the handlein a retracted position.

Embodiment 60: The container according to Embodiment 59, wherein thehandle is integral with the receptacle.

Embodiment 61: The container according to Embodiment 59 or Embodiment60, wherein the receptacle includes a base portion having of slot forreceiving at least part of a handle of a corresponding container.

Embodiment 62: The container according to any one of Embodiments 58 to61, further including a lid having a slot through which the handle isextendable to an extended position.

Embodiment 60: The tissue processor according to any one of Embodiment28 to 53, further including the container for storing tissue samplesaccording to any one of Embodiments 54 to 62.

Where any or all of the terms “comprise”, “comprises”, “comprised” or“comprising” are used in this specification (including the claims) theyare to be interpreted as specifying the presence of the stated features,integers, steps or components, but not precluding the presence of one ormore other features, integers, steps or components.

It is to be understood that various modifications, additions and/oralternatives may be made to the parts previously described withoutdeparting from the ambit of the present invention as defined in theclaims appended hereto.

It is to be understood that the following claims are provided by way ofexample only, and are not intended to limit the scope of what may beclaimed in any future application. Features may be added to or omittedfrom the claim at a later date so as to further define or re-define theinvention or inventions.

1-34. (canceled)
 35. A method of operating a tissue processor forprocessing tissue samples, the tissue processor including: at least oneretort for receiving tissue samples; at least one container for storinga reagent; and at least one sensor arranged for fluid communication withone or both of the at least one container and the at least one retortfor measuring a measured purity level of a reagent, the method includingthe steps of: a) conducting reagent from the at least one container orthe at least one retort to the at least one sensor; b) automaticallymeasuring, by means of the at least one sensor, a measured purity levelof the reagent; c) checking whether the measured purity level meets apredetermined purity level of the reagent associated with the at leastone container; and d) automatically determining, based on a result ofthe checking, whether the reagent is suitable for processing tissuesamples in the tissue processor.
 36. The method according to claim 35,further including the step of: providing the predetermined purity levelof the reagent based on reagent data for the at least one container. 37.The method according to claim 36, further including the step of:receiving, at the tissue processor, the reagent data for the at leastone container from a user.
 38. The method according to claim 37, whereinthe tissue processor further includes an input device, and the receivingstep includes receiving the reagent data by means of the input device.39. The method according to claim 36, wherein the reagent data includesat least a concentration value of the reagent.
 40. The method accordingto claim 35, which is performed when operating the tissue processor toperform a tissue processing protocol using the reagent.
 41. The methodaccording to claim 35, wherein the tissue processor includes a reagentline connecting the at least one container and the at least one retort,wherein the at least one sensor is arranged for fluid communication withthe reagent line, and wherein the conducting step a) includes conductingreagent in the reagent line between the at least one container and theat least one retort.
 42. The method according to claim 41, wherein theat least one sensor is one of: positioned in the reagent line; orpositioned in a bypass line that receives a portion of the reagent whenthe reagent is conducted in the reagent line.
 43. The method accordingto claim 35, which is performed on one or both of: filling of the atleast one retort with reagent; and draining of the at least one retortto remove reagent.
 44. The method according to claim 43, furtherincluding the step of: operating the tissue processor to stop filling ordraining of the at least one retort to perform at least steps (b)-(d),and wherein operating the tissue processor to stop filling or drainingincludes one or both of: operating the tissue processor to stop fillingprior to reagent contacting tissue samples stored in the at least oneretort; and operating the tissue processor to stop filling prior toreagent being delivered to the at least one container.
 45. The methodaccording to claim 43, wherein when the reagent is determined to besuitable for processing tissue samples, the method further includes thestep of: operating the tissue processor to continue filling or drainingof the at least one retort to complete a tissue processing protocol. 46.The method according to claim 43, wherein when the reagent is determinedto be unsuitable for processing tissue samples, the method furtherincludes the step of: operating the tissue processor to abandon thetissue processing protocol.
 47. The method according to claim 35,wherein the tissue processor includes a first container for storing afirst reagent and a second container for storing a second reagent, andwherein the method further includes the steps of: operating the tissueprocessor to perform a tissue processing protocol using the firstreagent and the second reagent; and automatically determining a carryover volume of the first reagent from the first container into thesecond reagent from the second container.
 48. The method according toclaim 47, wherein automatically determining the carry over volumeincludes the steps of: providing an initial volume of the second reagentin the second container; and performing the measuring step b) to measurethe following: a density value of the first reagent on draining of theat least one retort; a density value of the second reagent on filling ofthe at least one retort; and a density value of the second reagent ondraining of the at least one retort, wherein the carry over volume iscalculated according to:$V_{CO} = {\frac{\rho_{C\; 2_{out}} - \rho_{C\; 2_{in}}}{\rho_{C\; 1_{out}} - \rho_{C\; 2_{out}}} \times V}$wherein: V_(CO)=volume of carry over (L); ρ_(C2) _(out) =measureddensity value of the second reagent on draining of the at least oneretort (kg/m³); ρ_(C2) _(in) =measured density value of the secondreagent on filling of the at least one retort (kg/m³); ρ_(C1) _(out)=measured density value of the first reagent on draining of the at leastone retort (kg/m³); and V=initial volume of the second reagent in thesecond container (L).
 49. A tissue processor for processing tissuesamples, including: at least one retort for receiving tissue samples; atleast one container for storing a reagent; at least one sensor arrangedfor fluid communication with one or both of the at least one containerand the at least one retort for measuring a measured purity level of areagent; and a controller configured to: conduct reagent from the atleast one container or the at least one retort to the at least onesensor; measure, by means of the at least one sensor, a measured puritylevel of the reagent; check whether the measured purity level meets apredetermined purity level of the reagent associated with the at leastone container; and determine, based on a result of the checking, whetherthe reagent is suitable for processing tissue samples in the tissueprocessor.
 50. The tissue processor according to claim 49, wherein thecontroller is further configured to: provide the predetermined puritylevel of the reagent based on reagent data for the at least onecontainer.
 51. The tissue processor according to claim 50, wherein thecontroller is further configured to: receive, at the tissue processor,the reagent data for the at least one container from a user.
 52. Thetissue processor according to claim 50, wherein the reagent dataincludes at least a concentration value of the reagent, and wherein thepredetermined purity level of the reagent is a concentration leveldetermined based on the concentration value from the reagent data. 53.The tissue processor according to claim 49, wherein the at least onesensor measures a density value that represents the measured puritylevel of the reagent, and wherein the measured purity level is aconcentration value derived from the measured density value.
 54. Thetissue processor according to claim 49, wherein the controller isfurther configured to: operate the tissue processor to stop filling ordraining of the at least one retort to determine whether the reagent issuitable for processing tissue samples, and wherein the controlleroperates the tissue processor to stop filling or draining by one or bothof: operating the tissue processor to stop filling prior to reagentcontacting tissue samples stored in the at least one retort; andoperating the tissue processor to stop filling prior to reagent beingdelivered to the at least one container.